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THE NORMAL AND PATHOLOGICAL 
HISTOLOGY OF THE MOUTH 



VOLUME II 
PATHOLOGICAL HISTOLOGY 



By the same Author 

"An Introduction to Dental Anatomy 

and Physiology: Descriptive 

and Applied," 1913. 

"Dental Microscopy," a Handbook of 
Practical Dental Histology. 

First Edition, January, 1895. 
Second Edition, July, 1899. 
Third Edition, May, 1914. 



Part Editor of Tomes' 

"A Manual of Dental Anatomy" 
Seventh Edition, 1914. 




St. Uuis Dental Society 

The Normal and Pathological 
Histology of the Mouth 

BEING THE SECOND EDITION OF 

The Histology and Patho-Histolo 

OF THE 

Teeth and Associated Parts 

REVISED AND ENLARGED 
BY 

ARTHUR HOPEWELL-SMITH 

L. R. C. P., Lond., M. R. C. S., Eng., L. b! &., Eng. 

PROFESSOR OF DENTAL HISTOLOGY, PATHOLOGY AND COMPARATIVE ODONTOLOGY 
UNIVERSITY OF PENNSYLVANIA. PHILADELPHIA; JOHN TOMES PRIZEMAN OF 
THE ROYAL COLLEGE OF SURGEONS OF ENGLAND; MEMBRE HONORAIRE 
DE LA SOCIETE ODONTOLOGIQUE DE FRANCE; FORMERLY LECTURER 
ON DENTAL ANATOMY, SURGEON AND DEMONSTRATOR OF DENTAL 
HISTOLOGY AT THE ROYAL DENTAL HOSPITAL OF LONDON; 
MEMBER OF THE FACULTY OF MEDICINE OF THE UNIVER- 
SITY OF LONDON; EXTERNAL EXAMINER IN DENTAL 
SURGERY AT THE UNIVERSITIES OF BIRMINGHAM, 
LEEDS AND LIVERPOOL; LECTURER ON DENTAL 
SURGERY AND PATHOLOGY AT THE NA- 
TIONAL DENTAL HOSPITAL, LONDON 

VOLUME II 



PATHOLOGICAL HISTOLOGY 



• - * . 



WITH 394 ILLUSTRATIONS 

IN THE TEXT, INCLUDING ,343 ORIGINAL PHOTOGRAPHS 

AND PHOTOMICROGRAPHS BY THE AUTHOR 

X467G61 

PHILADELPHIA 

P. BLAKISTON'S SON & CO. 

1012 WALNUT STREET 



DEWTAL SCHOOL 



v 



Cf 



Copyright, 1918, by P. Blakiston's Son & Co 



THE MAPLE PRESS YORK I* A 



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flari I 

THE DENTAL TISSUES 

CHAPTER I 

Page 

The Pathological Conditions of the Enamel 4 

Introduction. Developmental Affections. Hypoplasia — Its Defini- 
tion, Etiology, Gross Anatomy and Histology — Enamel Nodules — 
Pathological Pigmentation — Nanoid Enamel — Rachitic and Syphili- 
tic Lesions. Acquired Affections. Abrasion — Absorption — Its 
Definition, Varieties, Etiology and Histology — Attrition — Erosion 
— Its Definition and Etiology — Views as to the Latter — Its Gross 
Anatomy and Histology — Fungoid Excavation. 

CHAPTER II 

The Pathological Conditions of the Dentine 42 

Developmental Affections. Dilaceration — Its Definition, Etiology, 
Gross Anatomy and Histology — Gemination — Its Definition, 
Etiology, Gross Anatomy and Histology — Lacunar and Other 
Defects — Definition and Etiology — Congenital Pigmentation — 
Nanoid Dentine — Vascular Channels. Acquired Affections. Ab- 
sorption — Its Varieties, Definition, Etiology, Gross Anatomy and 
Histology — Adventitious Dentines — Varieties — Structure of the 
Areolar, Cellular, Fibrillar, Hyaline, and Laminar Types — Patho- 
logical Pigmentation — Senile Dentine. 

CHAPTER III 

The Pathological Conditions of the Cementum 80 

Developmental Affections. Cement Nodules. Acquired Affections. 
Osseous Ankylosis of the Teeth — Hyperplasia — Its Definition, 
Etiology, Gross Anatomy and Histology — Senile Cementum. 

CHAPTER IV 

Dental Caries 101 

Definition — Etiology — Phases of the Process — Caries of Nasmyth's 
Membrane — Histology of "White Spots" — Penetration of Enamel 

vii 



VU1 CONTENTS 

Page 
by Micro-organisms — Zones in Enamel — Decalcification of Dentine 
— Zone of Translucency — Theories as to its Nature — Opaque Spots 
— Tubular Infection and Formation of "Liquefaction Foci" — 
Production of Cavities — Caries of Cementum — "Arrested" Caries 
— The Micro-organisms of Dental Caries — Epitome of the Histo- 
pathology of Caries. 

CHAPTER V 

The Diseases of the Dental Pulp 143 

General Characteristics — Hyperemia of the Pulp — Its Etiology — 
General Considerations — Special Histology — Acute Inflammation — 
Its Definition, Etiology, Terminations, Signs and Symptoms — 
General Histology of Inflammation — Special Histology — Conditions 
Associated with Non-penetrating Caries — Conditions Associated 
with Penetrating Caries — Chronic Inflammation — Its Etiology and 
Histology — Hyperplasia — Histology — Infective Gangrenej of the 
Pulp — The Pathogeny of Gangrene of the Pulp. 

CHAPTER VI 

Injuries of the Dental Pulp 174 

General Characteristics — Methods of Healing After Wounds, viz., 
After Small Traumatic Disturbances; After Wounds Involving Large 
Areas; After Carious Exposure; After Impacted or Non-impacted 
Fracture of the Hard Parts; After Injury Occurring in Cases of Non- 
exposure of the Pulp. 



CHAPTER VII 

The Degenerations of the Dental Pulp 187 

Histological Features of Fibroid, Atrophic, Fatty and Calcareous 
Degenerations. 

CHAPTER VIII 

The Pathology of the Pulp in Relation to Clinical Dental Surgery . . . 206 
Introductory — Carious Lesions — Lesions Due to Tactile, Thermal, 
Chemical and Electrical Stimulations — Referred Pain and Obscure 
Reflex Acts — Receptivity of the Pulp; Its Hyperesthesia and 
Dyaesthesia — Phases of Degeneration. 



CHAPTER IX 

The Vascular Lesions of the Dental Pulp 232 

Introductory — Anatomical Considerations— General Effects — 
Histo-pathology — Causes — Clinical Significance. 



CONTENTS IX 

Page 
CHAPTER X 

The Morbid Affections of the Alveolo-dental Periosteum 254 

Inflammation — Its Etiology, Gross Anatomy and Histology — 
Abscess — Dental Cysts — Definition, Etiology, Gross Anatomy and 
Histology — Tumours of the Periodontal Membrane — Those Belong- 
ing to the Type of the Lower Connective Tissues — Those Belong- 
ing to the Type of the Higher Connective Tissues — Carcinoma. 

CHAPTER XI 

"Pyorrhea Alveolaris" 271 

Introductory — The Gingival Margin — The Periodontal Mem- 
brane — The Apical Region — The Cementum — The Bone of the 
Jaw — Conclusions — Normal Arrangement of the Osseous and 
Fibrous Tissues — Early Changes Producing Osseous Atrophy — 
Absorption by Granulation Tissue — Chronic Periostitis and Senile 
Changes — "Pockets" — Anatomical and Clinical Observations — 
Summary. 

CHAPTER XII 

Degeneration of the Periodontal Membrane 306 

Introductory — The Fibrous and Cellular Tissues — The Areolar 
Spaces — Changes in the Neighbourhood. 



THE ORAL TISSUES 



CHAPTER XIII 



The Pathological Conditions of the Gums, Palate, Antrum and Jaws. ... 322 
Inflammation of the Gum — Hypertrophy of the Gum — Fibroma — 
Sarcoma — Endothelioma — Papilloma — Hemangioma — Osteoma 
— Adenoma — Carcinoma — Syphilis — Inflammation and Carcinoma 
of Lining Membrane of the Antrum of Highmore — Tumours of the 
Jaws. 

CHAPTER XIV 

Diseases of the Oral Mucous Membrane 354 

Inflammation — Tuberculosis — Malignant Degeneration. 



CHAPTER XV 

Odontomes and Odontoceles 371 

Definition — Classifications — Epithelial Odontomes — Origin, Gross 



X CONTENTS 

Page 
Anatomy and Histology — Follicular Odontomes or Dentigerous 
Cysts— General Considerations — Origin of the Cystic Fluid — His- 
tology — Compound Follicular Odontomes — Radicular Odontomes — 
Composite Odontomes — Histology — Odontoceles — Introductory — 
Classification of Species of Cysts of the Jaws — A Sub-capsular 
Odontocele — An Extra-capsular Odontocele. 

CHAPTER XVI 

Oral Microbiology 409 

Introduction — Classification of Plants — Classification of Bacteria 
and Protozoa — Microscopical Examination of Oral Material — 
Pathogenic Organisms — The Pyogenic Cocci — Filterable Viruses — 
Adventitious Bacteria of the Mouth — Micro-organisms of Dental 
Caries. 



fJart JJJ 

THE EXTRA-ORAL DENTAL TISSUES 

CHAPTER XVII 

"Dermoid" Teeth or Teeth Developed in Tcratomata 459 

Relations of Teeth to Tcratomata — Varieties — Eruption — Develop- 
ment — Shedding — Anatomy and Histology — Bony Attachments — 
Relation of "Dermoid" teeth to Hair — "Dermoid" Teeth in the 
Testis — Conclusions. 



PART I 

THE DENTAL TISSUES 




INTRODUCTION 

In considering the many pathological conditions of the hard and 
soft tissues found in the oral cavity, it is convenient to arrange, 
group, and describe them according to an anatomical, pathological, 
or clinical point of view. Each method of treatment is of value, 
but is dependent upon the character of the work for which it is 
made. Thus the clinical viewpoint is of vast importance in manuals 
dealing with the practice of Oral and Dental Surgery, and it is 
obvious that the anatomical should be of interest in a book dealing 
with Histology and Pathology. 

Hence it follows that, as far as is consistent and convenient, 
the arrangement of the Morbid Affections of the mouth and con- 
taining organs in this and succeeding Chapters is built upon the 
morphology and minute anatomy of the tissues. 

Regarding the diseases of the hard dental tissues many of 
which are quite unique, it is necessary to point out the fact that few 
are confined exclusively to one tissue, but that often the surrounding, 
or sublying structures share them also. The whole of the arbitrary 
classifications hereafter adopted, in order to save confusion, must 
therefore be considered in this light. 

In the three following and other Chapters the various lesions 
are placed in alphabetical order. 

The subjects of dental caries and "pyorrhaea alveolaris" have 
been specially relegated to Chapters by themselves. 

As far as the diseases of the soft Oral and Dental tissues are 
concerned, they differ essentially in no characteristics from morbid 
conditions of other cellular and fibrous structures. The phenomena 
of inflammation proceed on identical lines with those elsewhere. 
The structure of tumours of the jaws is in agreement with that of 
those which affect other regions of the body. In consequence, 
however, of their environment, the usual histological and patho- 
logical appearances are modified to greater or less degrees, and hence 
are peculiarly interesting and important. 




CHAPTER I 

THE PATHOLOGICAL CONDITIONS OF THE ENAMEL 

Microscopical Elements in: — (i) Hypoplasia; (ii) Enamel nodules; (iii) 
Pathological pigmentation; (iv) Nanoid enamel; (v) Rachitic enamel; 
(vi) Syphilitic enamel; (vii) Abrasion; (viii) Absorption; (ix) Attri- 
tion; (x) Erosion; (xi) Fungoid excavation. 

A. — DEVELOPMENTAL DISEASES 

(i) Hypoplasia 

Definition. — Enamel, the surface of which is more or less covered 
with pits, or fissures, not due to absorption. The term indicates 
fairly accurately the condition in which the enamel is not only re- 
duced in amount and thickness, but is developmentally defective. 
It is the antithesis of hyperplasia, where, as in the case of cementum, 
the tissue is increased in bulk. The old term, "honeycombed teeth," 
is falling into desuetude, as it should do, inasmuch as it is an incor- 
rect and misleading expression. Hypoplasia was originally called 
by Salter 1 "Rocky" enamel. The condition may be (i) general 
or (ii) local. 

Etiology. — The factors concerned in the production of (A) General 
hypoplasia of the enamel are not absolutely determined. Most 
probably (i) the exanthematous fevers, when sufficiently acute, 
particularly measles and scarlet fever, occurring during the first and 
second year after birth, are the chief. The pathological changes 
have also been ascribed (ii) to the effect produced on the ameloblasts 
by the exhibition of mercurial salts for the relief or cure of 
convulsions during the dentition of the child, (iii) Lamellar cata- 
ract is often accompanied by hypoplasic enamel. The condition 
is more likely to be occasioned (iv) by malnutrition from im- 
proper dietary. At all events, it is certain that it is due to modified 
function or altered metabolism on the part of the ameloblasts when 
they are most actively engaged in depositing lime salts, probably 
by the process of secretion. This would account for the granular 

1 Salter's "Dental Pathology and Surgery," p. 74, 1874. 

4 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 5 

appearance of the rods to be presently noticed. Exactly how the 
indentations or crevices themselves are formed is not known: it 
may be that some perverted state of Nasmyth's membrane may 
cause them. 

Suppuration around the root or roots of deciduous teeth may in- 
duce, (B) Local manifestations of the disease in the crowns of their 
permanent successors. 

Hvpoplasia of the enamel is said to occur in deciduous teeth, 1 
but care should be taken to discriminate between hypoplasia and 
absorption of this tissue. 




Fig. 1. — Vertical section of a cusp of a molar with hypoplasia of the enamel. 
Prepared by grinding. Unstained. Magnified 45 times. E. Enamel; F. 
Fissure; p. Pit extending to the margin of the dentine; d. Dentine. 

Macroscopical Appearances. — The most prominent features of 
hypoplasia of the enamel are loss of substance, deepening of the 
normal pits and fissures of its surface in situations such as the pre- 
molars and molars where they exist normally, pigmentation, and 
loss of lustre. The normal amount of the enamel is considerably 

'Otto Zsigmondy, "Beitrage zur Kenntniss der Entstehungsursache der 
Hypoplastischen Emaildefecte." Trans. World's Columbian Dental Congress, 
p. 48, 1894. 



THE DENTAL TISSUES 




Fig. 2. — Sagittal section of an incisor. Prepared by grinding. Unstained. 
Magnified 45 times, e. Deeply pigmented hypoplasic enamel; i.l. "Interrup- 
tion lines;" Fi. Fissure or pit on labial surface; F2. Pit on lingual surface; D. 
Dentine. Cf. Fig. 12, Vol. I. 



PATHOLOGICAL CONDITIONS OF THE ENAMEL J 

reduced in extent. In the molars, as well as in other teeth, a pro- 
nounced line of demarcation often divides the ill from the well- 
developed. The shrunken appearance of the crowns of molars seems 
to heighten the effect of the elevation of the cusps, several of which 
may be raised to pointed conical eminences. The enamel, in addi- 
tion to loss of its characteristic appearance 1 may be pigmented a 
brown or yellow colour. 

In the incisors and canines the pits or grooves are sometimes very 
numerous and small, running either in a vertical or a coronal di- 
rection. Sometimes they are distributed uniformly over the crown, 
and give it a spotted aspect. 

The extent of the hypoplasia varies. The commonest condition 
is that the crown of the first permanent molars, incisive edges and 
part of the crowns of the incisors, and the cusps of the canines are 
affected, the degree in each case of severity being similar, but of 
extent unequal. 2 

Secondary Changes. — There may be no secondary changes, the 
enamel undergoing no further alterations. But usually, marked 
pigmentation occurs, and caries attacking the depressions, especially 
when the dentine is exposed at the base of the cavities, may lead to 
fracture and loss of the tissue. "Arrested caries" may also occur. 

HISTOLOGY 

The most striking appearance, as viewed under low power, is the 
deeply pigmented condition of the enamel. Dense bands of brown- 
ish colour extend throughout its substance, being particularly 
pronounced in the neighbourhood of the breaches of surface (Fig. 
i). Brown and grey stripes — "interruption lines" alternate, 
with little or no attempt at regularity (Fig. 2). The brown 
striae of Retzius, in the majority of sections, are wanting, as also 
are Schreger's lines. 

A diminution in the normal width of the enamel is a remarkable 

1 As a matter of fact, the enamel is often quite white, shiny, and smooth in the 
areas between the depressions. 

2 In this connection it is of interest to recall the facts that "calcification cen- 
tres" appear in the tooth germs of the first permanent molars about the eighth 
month of intra-uterine life, in the incisors about the first year of post natal life, 
and in the canines about the third year of post natal life. For detailed accounts 
of the calcification of the teeth generally, see the author's "An Introduction to 
Dental Anatomy and Physiology: Descriptive and Applied," 1913. 



8 



THE DENTAL TISSUES 



feature. This occurs chiefly at the sites of the excavations or sulci, 
though it is certain that the thickness of the tissue generally is not 
so great as usual. The surface is smooth and rounded. 

Under higher magnifications the most internal stained areas 
are seen to consist of masses of coarse granules, the rods individually 
being ill-formed and structureless. The brown patches at the 
periphery of the enamel, however, show that the striae resident in 
the rods are very pigmented, being stained brown (Fig. 5), while 
the intervals between the striae shine with a bright lustre. But on 




Fig. 3. — Similar to Fig. 1. Magnified 45 times, p. Pigmented enamel; 
I.s. Interglobular spaces in the dentine. 



the whole the rods are not specially stained. The inter-columnar 
cement substance is clear and homogeneous. At the free margin 
the rods again become opaque and devoid of any histological 
elements. 

The amelo-dentinal junction is sharply differentiated, and con- 
sists, as in normal conditions, of a linear series of myriads of con- 
vexities, each of which looks towards the dentine. The boundary 
is often crossed by many tubes and well-organised enamel spindles. 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 9 

A little distance below the dentinal surface rows of unusually 
large interglobular spaces may appear (Fig. 7). They correspond 
in position to the fissures of the surface. There may be one, 
two, or even three rows of the spaces. In most cases they are very 
long and very broad. They are the usual, but not necessarily 
constant concomitant of enamel hypoplasia. 

The dentinal tubules have apparently undergone no morpholog- 
cal alteration. The patho-histology of Nasmyth's membrane over 




Fig. 4. — The same as the preceding. Magnified 750 times. Shows the 
faulty, irregular character of the enamel rods, and the pigmentation of a faint 
"interruption line." 

hypoplasic enamel has never been fully investigated; but, according 
to J. G. Turner {Trans. Odonto. Soc. 1916) it may be considerably 
thicker than normal. 



(ii) Enamel Nodules 

Definition. — Small, solid, rounded, sessile bodies with white, 
shiny, smooth surfaces, situated below the necks of maxillary or 



IO 



THE DENTAL TISSUES 




Fig. 5. — Hypoplasic enamel. Ground thin. Unstained. Magnified 350 
times. Shows the prominence of the stria? of the rods through pigmentation, 
p. Patch of pigmentation; s. Marked striation of rods; s.e. Structureless enamel. 




Fig. 6. — Similar to the preceding. Magnified 250 times. G. Granular 
structure of the enamel rods; a. Amelo-dentinal junction; i.s. Interglobular 
spaces. 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



II 



mandibular molars with the dentine and cementum of which they 
are intimately connected. They have been classified 1 under the 
heading of composite odontomes. They are but rarely associated 
with the mandibular teeth. 

Etiology. — They are produced by the local development and cal- 
cification of an aberrant prolongation of a portion of an enamel 
organ, which, while the rest of the tooth-band has become atrophied 




Fig. 7. — Similar to the preceding. Prepared by grinding, and photographed 
immediately after mounting. Unstained. Magnified 40 times, i.l. "Inter- 
ruption lines;" i.s. Interglobular spaces. 

and non-existent persists in the region of the dental capsule, and 
after depositing lime salts disappears. 

Macroscopical Appearances. — These little neoplasms bear a re- 
markable resemblance in shape, colour and lustre to white pearls. 
They present a marked contrast to the dull surface on which they 
are located (Fig. 8). 

Secondary Changes. — As far as is known, they are unaffected by 
disease or retrogressive changes. 

1 "The Report on Odontomes" by the Committee appointed by the British 
Dental Association, 1014. 



12 



THE DENTAL TISSUES 



HISTOLOGY 

A nodule is a hard mass, apparently spherical, but in reality 
hemispherical or semi-lunar in shape, consisting of a thick tubercle 
of pigmented enamel, whose constituent parts are very feebly ma- 
tured. The rods are chiefly granular and homogeneous, and their 
transverse striae scarcely visible. The striae of Retzius and lines 
of Schreger may occasionally be found. The outermost surface is 
deeply coloured brown, the difference in the depth and gradations 




Fig. 8. — Four rric 



try molars showing typical enamel nodules. 



of the stain being due, apparently, to the coarseness or fineness of 
the granules. 

The free edge of the nodule is smooth and mammillated, while 
the attached margin is crescentic in outline and firmly adherent to a 
button of fine-tubed dentine, which, in itself, may exhibit structural 
defects, in the form of interglobular spaces. Enamel spindles and 
interglobular spaces, when they do occur, are filled with amorphous 
granular material. The crescents of the amelo- 
dentinal junction are not sharp, and many tubes 
cross the boundary. 

Very rarely, enamel nodules, with the patho- 
logical appearances just noted, are found imbedded 
in the periphery of the dentine of teeth (see Fig. 
Fig. q. — Max- 12). In these instances they preserve their cres- 
lllary molar cen j;j c outlines, the difference being that the dentine 

showing two . ° 

enamel nodules, does not project from the surfaces in the form of 
a tubercle or cone as is usually the case; though a 
cusp of dentine with radiating tubules does occupy the concavity 
of the nodule. 

Nasmyth's membrane probably does not exist as such on the 
exposed surface of the nodule. 




PATHOLOGICAL CONDITIONS OF THE ENAMEL 



*3 




Fig. io. — Vertical section of an enamel nodule. Prepared by grinding. Un- 
stained. Magnified 20 times, e.n. Enamel nodule; d. Dentine; a. Amelo- 
dentinal junction; H.c. Hyperplasic cementum. 




Fig. 11. — A portion of the preceding section. Magnified 250 times, g 
Granular characters of the enamel rods; p. Dense pigmentation of the enamel 
rods, totally obscuring their structure. 



14 



THE DENTAL TISSUES 



(iii) Pathological Pigmentation 

This, which is a natural condition in the enamel of some of the 
families of Rodentia, e.g., Beaver, Coypu, or certain Cetacea, as in 
the persistently-growing incisor (tusk) of the Narwal, is seldom 
observed in human enamel. It must be distinguished from the 
green deposits constantly observed on the labial or buccal surfaces 



FD 



EN 




DE 



Fig. 12.— An enamel nodule surrounded by hard tissues. Magnified 10 times. 
E.N. Enamel nodule; d. Dentine; f.d. Structureless dentine; c. Cementum; 
d.e. Detritus produced by grinding. (Section prepared by Douglas Cabell.) 

of the teeth of young children, due to the agencies of chromogenic 
bacteria, which probably primarily affect Nasmyth's membrane. 

Definition. — A brownish discoloration of the enamel of teeth. 

Etiology is unknown. The tissue changes most probably have 
their origin as a congenital defect. 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



15 



Macroscopical Appearances. — The enamel is bright and polished, 
but is stained a deep brown or yellow colour. 
Secondary Changes. — None. 

HISTOLOGY 

There is little to be said about the microscopical structure of 
this condition. High powers reveal the fact that there are no 
imbrication lines; but the terminations of the enamel rods seem to be 




HC 



Fig. 13. — Vertical section of molar having nanoid enamel. Prepared by 
grinding. Unstained. Magnified 15 times. E. Enamel; c. Clefts; D. Dentine; 
h.c. Hyperplasic cementum. 

covered with an opaque structureless narrow band of hard material, 
which is slightly laminated in a direction at right angles to the rods. 
Groups of rods running in a centrifugal direction possess yellowish 
striae, with yellowish cementing substance between. In thin sec- 
tions the colour is scarcely visible, but thicker masses of the enamel 
reveal the staining very well. 



i6 



THE DENTAL TISSUES 



In the sections examined by the author there were no stria? of 
Retzius or Schreger's lines or enamel spindles; and the tissue itself 
was not particularly structurally defective. 

(iv) Xanoid or Dwarfed Enamel 

Specimens of human teeth apparently exhibiting absence of 
enamel or partial suppression of this tissue are occasionally met 
with. In no case however, investigated by the author, has there 
been entire absence of enamel, though in each it is greatly attenuated 
and stunted in growth. 




Fig. 14. — Similar to the preceding. Magnified 35 times, e. Nanoid enamel; 

d. Dentine. 

Definition. — Loss of normal thickness of enamel, producing 
a dwarfed condition, probably from failure of nutrition of the 
enamel organ, with the consequent production of its premature and 
retarded growth. 

Etiology. — Perverted or loss of function of the ameloblasts. 

Secondary Changes. — Caries and fracture. 

Macroscopical Appearances. — The crowns of the teeth, which 
may themselves be fully developed, present rough lustreless sur- 
faces, stained somewhat a slight yellow colour. The probability 
that the chromogenic bacteria of the mouth, or organic post-mortem 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



17 



changes in the tissues have produced the staining, is very remote. 
In one unique instance, three of the four third molars in the same 
mouth shewed signs of loss of enamel immediately after eruption, 
and it is equally certain that caries was absent. In a tooth in the 




FtG. 15. — A section through the jaw of a young ricketty monkey during de- 
velopment, the deciduous and permanent teeth being in situ. Prepared by 
Weil's process. Magnified 20 times, e. Enamel of permanent tooth exhibiting 
the structural defects described in the text; d. Its dentine; p. Its pulp; m. 
Dentine of deciduous tooth. (The section was prepared by Sidney Spokes.) 

possession of the author, one tiny mound of enamel was observed 
by the naked eye; while, on microscopical examination, two very 
minute masses of enamel were discovered over one of the cusps of 
this anomalous tooth, which in itself was exceedingly dwarfed and 
misshapen. 



i8 



THE DENTAL TISSUES 



HISTOLOGY 

The striae of the enamel rods are very conspicuous, and the inter- 
columnar substance marked. A tinge of yellow pigmentation is 
discernible in places. Numerous microscopic clefts pass in from 
the free surface of the tooth for varying distances. These are not 
due to manipulative processes consequent on the act of making the 
section. 

The dentine is, as a rule, normal (Fig. 13); though in the last- 
named specimen, interglobular spaces and vascular canals were 
found in places. 




Fig. 16. — A portion of the preceding. Magnified 50 times. E. Enamel; 

d. Dentine. 



(v) Rachitic Enamel 

Little is known of this condition: but sections lent to the writer 
by Mr. Sidney Spokes, and photographed (Figs. 15 and 16) show 
that during development, certain large, numerous clefts possibly 
containing, in the recent state, soft material, can sometimes be 
observed on the inner aspect of the tissue. Measurements of the 
length of the longest of the spaces in this particular specimen showed 
them to be 0.5 mm. The photomicrograph, taken by the author 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



19 



from the original preparation, are of the parts in and around the 
evolving permanent tooth of a monkey affected by rickets, and are 
most likely perfectly similar to those obtaining in like circumstances 
in man. 




Fig. 17. — A section of a human syphilitic incisor. Magnified 175 times. It 
shows extremely imperfect enamel, the spaces of which do not contain living 
material, e. Structurally defective enamel; i.s. Interglobular spaces in den- 
tine. (The section was prepared and photographed by Leon Williams.) 

The enamel of the corresponding deciduous tooth was likewise 
affected, but in a slighter degree. 



(vi) Syphilitic Affections 

Definition.- — Certain misshapen, deciduous and permanent teeth 
associated with congenital and inherited syphilis. 



20 THE DENTAL TISSUES 

Synonyms. — "Pegged teeth," "Hutchinsonian teeth." 
Etiology. — They are the result of stomatitis, a secondary syphilitic 
lesion inherited by children, in which the influence of the inflamma- 
tion on the cells of the enamel organ and dentine papilla is perma- 
nently recorded in the surface and shape of the incisors, canines and 
first molars. 

The Spirochceta pallida, according to Cavallaro of the Univer- 
sity of Florence, "Nouvelles Observations sur la Dentition chez 
les Syphilitiques Hereditaires," 1909, can be demonstrated in the 
dental capsule, and in the pulp on the walls and in the neighbour- 
hood of the blood-vessels. 




Fig. 18. — A portion of the enamel from the preceding section. Magnified 
600 times. It shows lacuna-like spaces found in syphilitic enamel. (Photomicro- 
graph by Leon Williams.) 

In the same year, also, this organism was observed in the den- 
tal tissues by Professor Pasini of Milan, and Assistant Professor 
Lombardo of Modena. 

Macroscopical Appearances. — The maxillary incisors are most 
commonly affected, and present characteristic and unique appear- 
ances. These are (i) a slight notch or groove, crescentic in shape, 
on the cutting edge; and (ii) smallness of the teeth themselves, 
which have convex sides and rounded-off angles. 

The mandibular incisors are usually conical and small. 

Secondary Changes. — None. 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



21 



HISTOLOGY 

The surface is not absolutely smooth, but "contains pits which 
are filled with micro-organisms of a reddish-brown colour, thus 
indicating that caries is not in progress. The enamel rods are 
poorly calcified; large lacuna-like spaces, which appear to be filled 
with organic matter, are seen, some of which have radiating proc- 




Fig. 19. — Another portion from the same section. Magnified 800 times. 
(Photomicrograph by Leon Williams.) 

esses, while others communicate with the dentine by means of 
canals." (Leon Williams.) Other portions exhibit large cavities 
of various shapes. The dentine contains interglobular spaces 
(see Figs. 17 and 20). 

B. — ACQUIRED DISEASES 

The morbid affections of the enamel which have been acquired 
since its full maturity has been reached are of interest, because, 



22 



THE DENTAL TISSUES 



as a rule, they are inseparable from certain lesions of the neigh- 
bouring dentine and cementum. The dental pulp, entirely un- 
affected by the retrograde changes which have taken place in the 
development of the teeth, too, often suffers. Naturally also, local 
conditions play a great part in the immediate causation of this 
group of acquired diseases, although erosion probably of all enamel 
lesions may be predisposed to more by general systemic dyscrasia 
than by inflammatory conditions or physical disturbances of the 
mouth. 

(vii) Abrasion 

Definition. — A term applied to the rapid wasting and destruction 
of enamel and dentine by friction set up by foreign bodies. 




Fig. 20. — A portion of the dentine from the preceding section. Magnified 
250 times. It shows the interglobular spaces of syphilitic dentine. (Photomicro- 
graph by Leon Williams.) 

Etiology. — Injury by mechanical appliances around the teeth and 
friction from careless or excessive use of the tooth brush are said to 
be potent factors in its causation. 

Macroscopical Appearances. — The cavities on the surface of the 
crown are very flat, dull, rough and superficial, being stained some- 
what yellow. The outline is usually ovoid. Hyperaesthesia may 
or may not be present. 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 23 

Secondary Changes. — Caries, fracture, secondary dentine in the 
pulp chamber. 

HISTOLOGY 

Early stages show a breach of surface at the cervical region of the 
teeth, with loss of the thin edge of enamel and cementum. Pig- 
mentation is present. The dentinal tubes appear similar to those 
of attrition. There is this marked difference, however, between 
the two, viz., caries may proceed more or less rapidly in the former, 
and not at all in the latter. Later developments lead to softening 
of the dentine matrix, deeper invasion of micro-organisms, and 
destruction of the hard parts around the cavity. 

(viii) Absorption of Enamel 

There are two kinds of absorption of enamel — (a) external and 
(/3) internal. Both rare, the former may be, in its earliest stages, 
unassociated with absorption or any morbid change in the dentine, 
— though at times it may accompany absorption of both dentine and 
cementum — and proceeds from without inwards; while the latter 
is wholly an occasional accompaniment or corollary of the phenomena 
of dental caries, and proceeds from within outwards. 

Definition. — That loss of enamel substance after the tissues have 
been fully completed, which is due to pathological and not physical 
or physiological or mechanical causes. 

(a) External Absorption 

Etiology. — Probably sometimes the result of (a) acid solutions 
coming into immediate contact with the surface of enamel when 
there has been some localised suppuration: and sometimes {0) the 
effect on the enamel surface of the functional activities of osteoclasts. 
The anomaly, which is rare, can be observed in connection with the 
retarded eruption of teeth in apparently edentulous mouths, where 
inflammation of the soft parts in the neighbourhood of the tooth 
has been induced by pressure from artificial dentures. In certain 
cases brought under the immediate notice of the author (a) mal- 
placed canines undergoing moliminous eruption in an inverted 
position had been the cause in two instances; and in a third (b) an 
unerupted third mandibular molar was the affected tooth. 

Macroscopical Appearances. — As one type, the following descrip- 
tion may be given of one of these specimens. 1 The crown, retaining 

1 See " A Case of Retarded Eruption," by Warburton Brown. Journal Brit. 
Dental Association, June, 1900. 



24 



THE DENTAL TISSUES 



in some measure its original conical form, was deeply hollowed out 
by means of curious excavations, some of which penetrated the 
pulp cavity (see Fig. 21). The surface was pitted and brown 
in colour. Its cervical measurement was 22 mm., and a large cavity 
13 mm. in length, extended round the labial and distal surfaces when 
the tooth was viewed in its normal position. The enamel and 
dentine, as a thin shell, were complete over half the labial and half 
the mesial surface. 

The crown was greatly pitted, having a deep fissure in the distal 
surface, as is seen in the photograph (Fig. 22). It was attached 
to the neck of the tooth, mainly on its lingual aspect — (Fig. 23) — 
as. well as by means of a column of dentine in the central axis of the 





Fig. 21. Fig. 22. Fig. 23. 

Fig. si. — The labial aspect of the unerupted tooth described in the text: 
Fig. 22. — Its distal surface; Fig. 23. — Its lingual side. Note. — The surfaces 
of this tooth are named, as if the canine had finally erupted in a normal manner, 
and assumed a normal position in the dental arch. A. Deep excavation; B. 
Absorption extending to the pulp cavity, the side of which is seen at C. 



tooth, which occupied what was probably the original pulp chamber. 

The total area of enamel present was about 2 mm. square. 

The tooth generally was normal in size, yellowish in colour 
(indicating age), and had some slight amount of hyperplasia of the 
cementum over its apical region. 

Secondary Changes. — None usually; but, exceedingly rarely, 
deposition of bone. 

HISTOLOGY 



In (a) cases the minute anatomy is interesting, as Howship's 
foveolas, almost universally associated with absorption of the hard 
tissues of teeth or bone, are entirely wanting. The outlines of the 
cavity are irregularly flat or oval, possessing none of the round 
bay-like recesses seen in absorption in other tissues. Although 
these absorption-areas appear to be wanting, it would be difficult 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 25 

to explain the presence of such large excavations in the hard parts, 
if the question of osteoclastic activity were put entirely out of court. 
Hence it would seem reasonable to suppose that the greater pro- 
portion of the spaces had been produced by the functions of these 
cells. 



PE 




Fig. 24. — External absorption of enamel. Prepared by grinding, and stained 
by impregnation with coloured collodion. Magnified 40 times. E. Enamel of 
normal structure; p.e. Pigmented enamel; a. a. Absorption areas filled with 
osseous material; b. Trabeculas of compact bone; d. Dentine. 



The enamel rods appear as if broken off, and at the extreme edge 
there is a slight dissolution of their intercolumnar cement substance. 
There may be, or there may not be, some pigmentation of the parts. 

It is extreme conditions, and such as that already cited in full, 
which are accompanied by absorption of dentine. 

In the (/3) case of a specimen, probably quite unique, for which 



26 THE DENTAL TISSUES 

the author acknowledges his indebtedness to Sir Francis Farmer, re- 
markable absorption had occurred, and had been followed by a 
most unmistakable deposition of cancellous bone (see Fig. 24). 
Here the foveolae of Howship are clearly distinguished, loss of enamel 
having in some parts extended almost to the amelo-dentinal junc- 
tion. Osseous material, easily recognised macroscopically as well 
as by the microscope, occupied the excavations and practically 
restored the greater part of the absorbed crown of the tooth to its 
normal height. The history of the tooth in no wise suggested 
this interesting histological abnormality. 

(j3) Internal Absorption 

Etiology. — Caries of dentine. 

Secondary Changes. — Deposition of calcined material (osteo- 
dentine) may occur, as in the case recorded by Mr. J. A. Woods, 
"A case of Absorption," Journal British Dental Association, April, 
1902, pp. 193-197 (see Figs. 25, 26). 

HISTOLOGY 

In a letter to the author Mr. Woods describes the condition as 
follows: — 

"Mr. F. Rose, at a meeting of the British Dental Association, 
showed a partly absorbed maxillary third molar which he had re- 
cently removed. It came away without using any force and prac- 
tically left no socket, and only a very shallow crown. On naked eye 
examination it appeared to be merely the crown of a tooth, and to 
consist mainly of the enamel filled with a somewhat soft calcareous 
mass. He offered it for histological examination, and the report 
made at the next meeting was as follows: — 

"'On scratching the inner part a distinct grating noise could be 
heard, which pointed to calcareous elements. 

"'On proceeding to cut a section, I found it would be necessary 
to make an ordinary ground one, as a decalcified section would not 
show any of the soft tissues, which had already been destroyed 
by drying, etc. It was not possible to get a very thin section without 
running a great risk of destroying the part showing the new tissue, 
which, of course, was the most important portion. 

" 'The accompanying photomicrographs are taken from various 
parts of the one section and show most of the important points. 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



27 




Fig. 25. — Internal absorption of enamel, a. Enamel; b. Normal dentine 
very full of interglobular spaces; c. Cavity in the dentine formed by absorption 
and then deposition of "osteo-dentine; " d. Enamel penetrated and absorbed 
and filled in with "osteo-dentine." (Photomicrograph by J. A. Woods.) 




Fig. 26. — A higher magnification of the preceding, showing absorption of the 
dentine and enamel from the pulp surface, and deposition of "osteo-dentine." 
A. Enamel; b. Normal dentine; c. Deposition of "osteo-dentine" (?) in enamel. 
(Photomicrograph by J. A. Woods.) 



28 



THE DENTAL TISSUES 



" 'A low magnification showed that a large portion of the normal 
dentine had undergone absorption, and that in one part (a cusp of 
the molar) the inner surface of the enamel had been removed. All 
this normal tissue has been replaced by a mass of cancellous calca- 
reous tissue which can probably be best termed osteo-dentine. 




Fig. 27 — Vertical section of molar showing internal and external absorption 
of enamel and dentine. Prepared by the Koch-Weil process. Stained with 
Grenacher's alcoholic borax-carmine. Magnified 45 times, d. Primary dentine; 
B Compact but irregularly formed bone filling up pulp cavity; A. Compact 
bone filling up absorption area in primary dentine; c.b. Bridge of compact bone 
crossing over areas of internal and external absorption. 



'"Fig. 25 is a rather higher magnification of the same part. 
It will be observed that the dentine contains a large number of 
interglobular spaces; this, however, is not by any means uncommon 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 20. 

in third molars. It will also be observed that in several places the 
absorption has penetrated the dentine in different places, and so one 
section gives the appearance of several isolated patches of absorption. 

'"The deposited material consists of spicules as seen in cancellous 
bone, the spaces being probably filled in the recent condition with 
pulp matter. The presence of lacunae can be seen in various parts 
of the osteo-dentine. 

'"Fig. 26 gives a clearer view of the absorption of the dentinal 
surface of the enamel with the new material in situ. 

'"Another portion of the section shows a patch of cementum, 
part of which has been removed by absorption and osteo-dentine 
has taken its place.' " 

(ix) Attrition 

Definition. — Gradual wearing away of the hard parts through the 
physical and physiological agencies of mastication of food. 

Etiology. — A constant accompaniment of senility, it is probable 
that in the young it may occur under the influence of certain 
mechanical forces, the result of imperfect occlusion. In the former 
it is a general condition, in the latter localised. 

Macroscopical Appearances. — The morsal surfaces of molars 
present a bright polished flattened table-land of hard tissue. An- 
terior teeth may be worn away so that half the crown of the tooth 
may have disappeared (see Fig. 28). Tartar is often present over 
the roots of these teeth. 

Secondary Changes. — Fracture, formation of secondary dentine 
in the pulp. 

HISTOLOGY 

The enamel is very pigmented, and the rods are cleanly cut 
at right or acute angles to their courses. The primary dentine is 
free from caries, but slightly coloured in patches which run through- 
out its entire thickness. The dentine is cut transversely or tan- 
gentially, sometimes at right angles to the tubules, at others parallel 
with them. The cut is sharp, and looks as if made by a keen razor. 
Interglobular spaces are frequently present in greater numbers 
than usual. 

The secondary dentine is well formed and fine tubed, and fills 
most thoroughly the coronal and cervical regions of the former pulp 
cavity. 



3° 



THE DENTAL TISSUES 



(x) Erosion 

Definition. — Progressive destruction of the exposed surfaces of 
teeth, producing cavities which are peculiarly dense and polished, 
and in the majority of instances hypersensitive on receiving tactile 
impressions. 

Synonym. — " Cuneiform defects." 




Fig. 28. — Sagittal section of a human incisor, showing marked attrition of 
the crown. Prepared by grinding. Unstained. Magnified 12 times, a. Worn 
surface of the tooth; d. Dentine; s.D. Secondary dentine; p. Pulp cavity. 



Etiology. — Little is known as to the origin of this common con- 
dition which is found in the teeth of man the wide world over. Much 
has been written on the subject, and many experiments to induce 
it artificially have been performed. 

In England the lesion is usually ascribed to gout or allied diseases, 
affecting the small mucous glands of the lips or gums, by setting 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 3 1 

up a state of local congestion, and causing these bodies to pour out 
an acid instead of an alkaline or neutral secretion. This acid mix- 
ture attacks the enamel or dentine or cementum of teeth at their 
cervical margins, and decalcifies those tissues. 

It is exceedingly probable, however, that the condition is pre- 
disposed to by the denudation of dentine at the necks of teeth by the 
thin edges of enamel and cementum which, as a rule, overlap it, 
when — in other words — these two tissues do not meet bout a bout 
(see Chap. Ill, Vol. I). 

The action on or morbid changes in Nasmyth's membrane are 
entirely unknown. Tomes 1 attributes the affection to a chemical 
solution of the tooth from acids generated by the fermentation of 
mucus, or this material affording a suitable nidus for acid fermenta- 
tion. Salter combines abrasion and erosion under the inclusive 
title of " Surface wear," and he divides the causes into — 

(a) Predisposing — inherent softness of structure, as in syphil- 
itic teeth : 
(j8) Exciting — molar-mastication by incisors, gritty food, 
hard tooth-brush, and friction from wearing a denture. 

On the Continent of Europe, six chief views are held: — 

1. The Chemico-mechanical Theory, supported by Bastyr, 
Brandt, Sheff, Shlenker, and Walkhoff, in which an exceed- 
ingly thin layer of dentine is decalcified by the constant 
influence of weak acids generated in the mouth, and finally 
removed by mechanical means, such as tooth-brush, powders, 
etc.; 

2. The Mechanical Theory, due to attrition by friction of food, 
etc., advocated by Parreidt and Niemeyer; 

3. The Chemical Theory of Baume; 

4. Caries by Leber and Rottenstein, Magitot, 2 etc.; 

5. The Exfoliation Theory of Baume, which maintains the hy- 
pothesis that the superficial layers of the dentine not covered 
by gum or enamel "die," and fall off mechanically, the 
polishing of the denuded spaces being brought about by the 
rubbing of the lips, etc. ; 

6. The Dechondration or Decalcification of the Dentine Theory 
of Znamensky. 3 According to this careful observer enamel 

1 Tomes & Nowell: "A System of Dental Surgery," 1906. 

2 "Recherches sur la Carie des Dents, Paris, 1871." 

3 "On the question of the origin of the Cuneiform Defects of Teeth." Journal 
Brit. Dent. Assoc, pp. 8 et seq., 1898. 




2,2 THE DENTAL TISSUES 

plays no part in the process; but there is mechanical removal 

of isolated particles of lime salts in the eroded regions. This 

is due to "unequal abstraction of the 'gelatine-yielding' 

substances of the dentine," and the subsequent swelling of its 

organic constituents. 

Erosion sulci have been said to have been found on human teeth 

worn on a denture as substitute in case of loss, and also in ovarian 

teeth (see page 467). 

Macroscopical Appearances. — The cavity of erosion is a sharp- 
edged, smooth, highly polished groove at the necks of teeth, running 
transversely to their axes. In position, these acquired defects are 
most often seen on the labial or buccal aspects, and only very rarely 
over the lingual or palatal sides of the teeth. In outline they are 
more or less wedge-shaped, with edges sharply cut 
and well-defined. Their surfaces are smooth, 
bright and polished; by means of a hand lens, 
saucer-like cavities may sometimes be discerned. 
If these tiny subsidiary excavations or spaces exist 
in great numbers, they may impart a dull, even 
A B rough, surface to the floor and walls of the grooves, 

Fig. 29. — Max- which then may be stained any colour, from yellow 

aSmaxUlary left t0 brown > black ' or even g reen - In dee P grooving 
first premolar, the enamel is undermined. In number, as a rule, 
from mouth of a one , file-like cut is seen, but occasionally 

man aged 54, ° J 

showing erosion several exist on the cervical region of the teeth, 
fta/I/a/^surfaceT es P eciall y when a large portion is denuded. 

a. Distal aspect of 

canine, b. Mesial HISTOLOGY 

aspect 01 pre- 

The earliest evidence of change, according to 
Baume, is the presence of cup-shaped depressions analogous to 
Howship's foveolae, covering the eroded surface, which is now un- 
even. Fissures in the neighbouring dentine are simultaneously 
produced. Further internally placed, is a band of translucent 
dentine. 

Underwood has noticed (Journal Brit. Dent. Association, Vol. 
xix., pp. 470-2) a hitherto undescribed phenomenon connected with 
enamel the subject of erosion. This is the presence of exceed- 
ingly tiny interglobular spaces, with accompanying calcospherites 
(see photographs, Figs. 31 and 32). These spaces are apparently 
scattered throughout the tissue. The writer adds that the condition 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



33 




Fig. 30. — Coronal section of a human molar. Prepared by Weil's process. 
Magnified 15 times. E.c. Erosion cavity on buccal side of the tooth; d.t. 
Dentinal tubes which are probably completely calcified; e. Enamel; p. Pulp; 
p.T. Band of pulp tissue which has undergone some degenerative (?) changes. 
The small black masses in the pulp are probably clusters of borax crystals, 
deposited in this manner by the salts in Grenacher's alcoholic borax-carmine 
stain. 



34 



THE DENTAL TISSUES 



differs in every respect from the so-called erosion found in the teeth 
of Otaria, first described and figured by Murie in the Trans. Odonto. 
Soc. of Great Britain for 1870. 

The granularity of the rods is exaggerated. 

That the underlying dentine is affected in earlier stages of the 
disease is shown by the fact that the tubules are calcified throughout. 
That is to say, in sections of teeth prepared by the Koch-Weil 
process they refuse to stain, but maintain a dark black colouration 
through all their length (Fig. 30). 

The pulp has deposited a layer of adventitious dentine opposite 
the breach of surface. This is truly Salter's "dentine of repair" 




Fig. 31. Fig. 32. 

Fig. 31. — Erosion of enamel. Prepared by grinding. Unstained. Magnified 
750 times. Shows interglobular spaces and calcospherites. (Section from the 
collection of A. S. Underwood.) (Photomicrograph by Andrew Pringle.) 
Fig. 32. — Similar to the preceding. From the same source. (Photomicrograph 

by Andrew Pringle.) 

(see Fig. 34). Its structure is of an irregular, indefinite character. 
A well-organised system of tubes is wanting, though spaces of an 
unusual type may be found. In the photomicrograph (Fig. 35) 
the pulp exhibits a different pathological condition to that in the 
Figure on page t,^. The specimen is interesting, showing, as it 
does very clearly, the clefts described by Baume, the "dentine of 
repair," and the pulp undergoing retrogressive or fibrous changes. 



(xi) Fungoid Excavation 

Definition.- — The boring by fungoid organisms of large tubes in 
the hard parts of teeth. 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



35 




p IG 23. — Appearances mentioned in the text in the enamel of the sea-lion. 
(Photomicrograph by Andrew Pringle.) 



SD 




EC 



Fig. 34. — Erosion, showing deposit of "dentine of repair" on the internal aspect 
of the dentine. Magnified 40 times. E.c. Erosion cavity; s.d. Adventitious 
dentine. {Section prepared by Douglas Caush.) 



36 



THE DENTAL TISSUES 




EC 



Fig. 35. — Sagittal section of human incisor. Stained with haematoxylene. 
Magnified! '45 times, e.c. Erosion cavity on surface of which can be seen 
Baume.'s clefts; p. Pulp tissue undergoing degenerative changes; F.O. Atrophic- 
odontoblasts; s.d. Fibrillar adventitious dentine. {Prepared [by the Author's 
process.) 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



37 



Etiology. — It is supposed to be due to the peptonising or acidify- 
ing effects of a Saccharomyces equally in the substance of the enamel, 
dentine, and cementum. The condition is extremely rare. 

Secondary Changes. — None. 

HISTOLOGY 

Enamel, dentine, and cementum may suffer in different degrees. 
Two interesting cases have been recorded. Tomes {Trans. Odonto. 




Fig. 36. — Ground section of dentine and cementum. Unstained. Magnified 
20 times. D. Dentine; B. Excavations made by the fungus; c. Cementum. 
(From a specimen in the collection of Charles S. Tomes.) [Photomicrograph by 
Douglas Gabell.) 

Soc. Vol. xxiv., pp. 90-91) describes the first, where a tooth picked 
up in an ancient graveyard had presumably been buried for a great 
number of years. 

The dentine of the root was largely excavated in all directions 
by tunnels or channels of uniform diameter, which most probably 
were caused by a yeast, possibly one of the Saccharomyces. "In 



3§ 



THE DENTAL TISSUES 



many places the borings followed two directions, more or less at 
right angles to one another — the one being along the dentinal tubes, 
the other along places corresponding to those incremental layers, 
along which disintegrating dentine so often breaks up. Where 
the dentinal tubes were traversed, the enlarged portion passed ab- 
ruptly into that which was unchanged, so that the idea of a mere 



I 







Fig. 37. — Similar to the preceding, and from the same source. Stained with 
carmine. Magnified 40 times. B. Borings in cementum. (Photomicrograph 
by Douglas Gabell.) 



chemical solvent creeping down the tubes was negatived. And 
although its usual course was along lines which might be regarded 
as those of least resistance, it was perfectly capable of drilling the 
dentine in any direction whatever, as is seen in Fig. 36, in which 
the tunnelings were in all directions, quite irrespective of the tubes 
or the lines of growth." 

"These sections prove that a fungus can, unaided or aided only 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 



39 



by the decomposition of the organic material present in dentine, 
drill freely in any direction." 

Penetration of the cementum is clearly seen in Fig. 37. 

The second instances are those recorded by Professor Duckworth, 
of the Physical Anthropology Laboratory at Cambridge University. 
{Trans. Odonto. Soc. of Great Britain, Feb., 1901, p. 89), in an article 
entitled "Some dental rudiments in Human Crania." In these 




Fig. 38. — Similar to the preceding. Stained with carmine. Magnified 160 
times. (Photomicrograph by Douglas Gabell.) 



tiny calcareous fragments, which probably represented vestigial 
third premolars (similar to those of the New World Apes), true 
dental tissues were found, the enamel and cementum of which were 
channelled through and through with the borings made by one of 
the Blastomycetes. 

The fragments came under the personal notice of the author, 
who in a microscopical report wrote: "Specimen No. 2154 (e) 



4o 



THE DENTAL TISSUES 



Columns (probably enamel), chiefly seen in transverse section, 
though sometimes longitudinally cut. Not very brightly outlined, 
nor possessing marked striae, nevertheless clear and unmistakable. 
Numerous large tubes or channels with bulbous or rounded ex- 
tremities run here and there throughout the tissue." "Root 
portion of tooth. Dentinal tubes are marked and when filled with 
detritus from grinding very black. Cementum thick, few lacunae 




Fig. 39. — Channelling of the enamel. Prepared by grinding. Magnified 
50 times, e. Enamel; c. Sinuous tube passing from without inwards to end 
at, a. The amelo-dentinal junction; d. Dentine. (Photomicrograph by Douglas 
Gabell.) 



and canaliculi, but incremental lines very apparent. Traces here 
and there of fungoid burrowing. Specimen No. 2154 (n) Transverse 
section of dentine. Cementum practically structureless. Large 
channels produced by Saccharomyces mycoderma, confined, in this 
preparation to the cementum; granular layer marked." 



PATHOLOGICAL CONDITIONS OF THE ENAMEL 4 1 

Abnormal channelling of the enamel has been known to occur. In 
the specimen, from which Fig. 39 was reproduced, a long winding 
canal can be observed leading from the periphery of the tooth to 
the amelo-dentinal junction which it did not pierce. There is no 
history of the case. It is certainly a developmental error; but its 
method of formation is absolutely unknown. 



CHAPTER II 

THE PATHOLOGICAL CONDITIONS OF THE DENTINE 

Microscopical Elements found in: — (i) Dilaceration; (ii) Gemination; 
(iii) Developmental defects; (iv) Pigmentation; (v) Nanoid dentine; 
(vi) Vascular Canals; (vii) Absorption; (viii) Adventitious Dentines; 
(ix) Pathological Pigmentation; (x) Senile Dentine. 

A. — DEVELOPMENTAL DISEASES 

(i) Dilaceration 

Definition. — A permanent malformation of the teeth, usually in 
their cervical or radicular portions, in which the hard parts are 
deviated from the axial straight line in such a way as to form an 
angle with it. 






Fig. 


40. 


Fig. 


40. 


Fig. 


41. 


Fig. 


42. 


Fig. 


43- 



Fig. 41. Fig. 42. Fig. 43. 

-Dilaceration of maxillary first incisor. 
-Dilaceration of another maxillary first incisor. 
-Dilaceration of maxillary first premolar. 
-Dilaceration of maxillary second premolar. 



Etiology. — It is generally believed that a severe blow in the mouth 
may at times produce such an injury to the developing tooth or 
enamel and dentine germs as to cause — if the traumatism is not too 
great — that error of development to which the term dilaceration 
has been and is still applied. The incautious removal of the decidu- 
ous predecessor of a permanent tooth may likewise occasion it. 
The anterior teeth, with the exception, perhaps, of the canine, are 
most commonly affected. 

Macroscopical Appearances. — The tooth may be curved at its 
neck or anywhere along the extent of its root. This bending may 

42 



PATHOLOGICAL CONDITIONS OF THE DENTINE 43 

be a mere continuous flexion of its outline, the apex of the root 
terminating in a normal manner; or there may be a double curvature. 
More rarely the crown appears to be joined to the neck of the tooth 
almost at a right angle or acute angle. Again, the crown may be 
apparently impacted in the body or root of the tooth. Superficially 
examined, there are no indications of morbid changes, except perhaps 
the occasional appearance of a mal-formed crown and a hyperplasic 
condition of the cementum. 
Secondary Changes. — None. 




Fig. 44. Fig. 45. Fig. 46. 

Fig. 44. — Dilaceration of a mandibular third molar. Occlusal surface show- 
ing convolutions of the crown with pigmented intervening fissures. 
Fig. 45. — The same. Lingual aspect. 
Fig. 46. — The same. Buccal aspect. 

HISTOLOGY 

At the seat of injury the dentinal tubules pursue a course which is 
far longer than normal. They are also strongly curved. The 
dentine at the point of curvature may sometimes exhibit signs of 
absorption on its cortical aspect, with subsequent deposition of 
cementum. The pulp canal retains its central position. The 
granular layer of Tomes is highly pronounced and thickened; and 
cemental hyperplasia, a result of chronic inflammation of the perio- 
dontal membrane, is present (see Fig. 48). The cementum of 
the parts unaffected by traumatism is normal and devoid of 
lacunae, though its lamination is marked. 

In dilaceration of the cervical region, a condition less common than 
that just described, the amelo-dentinal junction is bent on itself, 
and at times exhibits signs of absorption. This may contain hyper- 
plasic cementum or enamel. The latter tissue may or may not be 
normal in structure. At times, however, a fissure or fissures, or 
even a canal, may exist, as in Fig. 39. 

(ii) Gemination 

Definition. — The union of two or more teeth. There are two kinds 
of gemination (i) True, (ii) False. Of these "True" gemination 



44 



THE DENTAL TISSUES 



is the term applied to those teeth which are joined to one another by 
some cause which operates during developmental periods, and 
without the aid of inflammatory conditions of the root membrane, 
"False" gemination when the osteoblasts of the root membrane, 
as a result of productive periostitis, have laid down an overgrowth 




Fig. 47. — Dilaceration of the cervical region of a human incisor. Prepared 
by grinding. Unstained. Magnified 12 times. E. Normal enamel; 1. Involu- 
tion of enamel into the dentine by penetration of the amelo-dentinal junction, 
probably the result of absorption; h.c. Hyperplasic cementum at seat of dilac- 
eration; s.c. Normal structureless cementum; D. Dentine. 



of the cementum. It follows, from this definition, therefore, that in 
the former, enamel and dentine may generally constitute the ma- 
terial which unites the teeth, while in the latter hyperplasic ce- 
mentum is the bond of union. As a rule members of the same 



PATHOLOGICAL CONDITIONS OF THE DENTINE 



45 




Fig. 48. — Dilaceration of the radicular region of a human canine. A second 
smaller curvature, not shown in the photomicrograph, existed near the apex of 
the tooth. Prepared by grinding. Unstained. Magnified 15 times. Shows 
enormous thickening of the hyperplasic cementum. d. Dentine: h.c. Cemen- 
tum; g. Granular layer of Tomes. 






~~.-.: 7 : . . . : - - 7 dse 




■ "_i me ■ Uf r_-v. '- ■ ■-.'.- z 



* 






Imtion, or it may be doe to faaoa of two or three tooth germs. This 
c ommonfe - occmrs in a paraBd direction: bat not always. The teeth 
mar be jwiined thnmghont their 1—grW wholly or partialhr. 

la. tbe deewmoas series the mandibular incisois and canines 
are most frequently grminated Thns tbe first and second incisors 
. - - - •- - 




rzrdy tbe two incisors and a snpennnneiary tooth (Figs. . tnd 

In tbe pennanent dentition supernumerary teeth are often 

geminated to molars or incisors, ; shows an example of a 

dwarfed snpetmnnerary tooth geminated to a small third molar. 

k a grmrine case of true gemination, as the dentine is normal 
and presents no signs of the changes observed in certain odontomas. 

Fig. 50 shows fake gemmation of three maxillary molars— a 



?aT3l : i :<:-;.>_ ;■::•>_ iti. :■■"? j 



* - - = - Zr.Z< 






j - - 



: - T 



{ 

* 



:: *' 

:<: :.r ~ . "_" l; ~.t~i~. .~i~. ..- r Ki 

~7l: z.Z~.i:~ IO_ r .."" 1- . :- -': ' " - - ~ 




• ' I " . =■»- 






Msrattraoi; a masmaH coniBuuii, w:r t<: 



48 



THE DENTAL TISSUES 




PM 



Fig. 53. — True gemination of a third maxillary human molar with an in- 
verted impacted conical supernumerary tooth, as described in the text. Pre- 
pared by grinding. Unstained. Magnified 15 times, r. Pulp canals in the 
extremely divergent roots of the molar; p.m. Its pulp cavity; d.s. Dentine 
of supernumerary tooth; p.s. Its pulp cavity; H.c. Hyperplasic cementum. 



PATHOLOGICAL CONDITIONS OF THE DENTINE 49 

HISTOLOGY 

The diagrams reproduced in Figs. 54, 55, and 56 represent 
horizontal sections of true gemination of the mandibular deciduous 
first and second incisors, and a small supernumerary tooth, and 
reveal the facts that near the cervical margins three pulp chambers, 
separate and distinct from each other, each having normal radiating 
fine-tubed dentine exist. The enamel, as a narrow cervical ring, 
surrounds each segment of the tissue. Lower down two pulp 
chambers, one rounded and the other dumb-bell shaped, are formed 
(Fig. 55). The dentine, normal in every particular, intervenes 
between the pulp cavities. A section near the apex of the root shows 
that the two pulp cavities have become merged into one. In every 
instance the dentine and cementum are unaffected by morbid 






Fig. 54. Fig. 55. Fig. 56. 

Fig. 54. — Horizontal section of three geminated teeth at cervical region, where 
there are three pulp chambers. 

Fig. 55. — The same, showing two root canals. 
Fig. 56. — The same, showing one root canal. 



changes, the latter being merely a very attenuated annular layer of 
solid osseous material. 

In Fig. 53 there is a strong suggestion of the impaction of a 
supernumerary tooth in the midst of the third molar producing a 
cleavage of the tooth germ. It is a curious anomalous condition, 
and probably unique. 

The dentine exhibits the usual characteristics, but the enamel 
has been removed in process of grinding the specimen, while the 
cementum is hyperplasic, indicating, no doubt, that an injury had 
been received by the immature tooth germ. Embracing the neck 
of the supernumerary tooth the cementum of the molar is continued 
outwards, on one side as a fine triangular peninsula of hard tissue, 
on the other as a rounded cone-like elevation. 

The root canals of the molar can be clearly followed almost to the 
apices of these cemental and dentinal projections. 



50 THE DENTAL TISSUES 

Diphyodontic Gemination 

There have recently come into the possession of the author two 
examples of this condition, in which, as already stated, a deciduous 
tooth may become firmly united to a member of the permanent 
series. The first, [which has no available history], illustrated in 
Figs. 57 and 58, is a left maxillary first incisor removed from the 






Fig. 57. Fig. 58. Fig. 59. 

Fig. 57. — Diphyodontic gemination of a maxillary left permanent first incisor. 
Labial aspect. 

Fig. 58. — Diphyodontic gemination. Same specimen as preceding. Mesial 
aspect. 

Fig. 59. — Mandibular left permanent second incisor affected by diphyodontic 
gemination. Labial aspect. 

mouth of a child of ten or eleven years old. The labial surface measures 
18 mm. in length, it is 9 mm. wide, the normal measurements of a simi- 
lar tooth being 12.5 mm. and 9 mm. respectively. The mesial 
surface of the root is 7 mm. the distal 6 mm. in extent. The root 
was deflected toward the mid-line, its apex was still patent. The 







Fig. 60. Fig. 61. Fig. 62. Fig. 63. 

Fig. 60. — Similar to preceding. Lingual aspect. 

Fig. 61. — Similar to preceding. Distal surface. 

Fig. 62. — Similar to preceding. Mesial surface. 

Fig. 63. — Similar to preceding. Occlusal surface. 

length of the deciduous attached crown measured 10 mm., its width 
6 mm. 

The second case for which the author is indebted to Dr. Edward 
C. Kirk, occurred in the mouth of a girl aged fourteen years. It is 
a left mandibular second incisor. It was said to have erupted at the 
eighth year, and, so the patient affirms, followed a deciduous prede- 



PATHOLOGICAL CONDITIONS OF THE DENTINE 5 1 

cessor. Its position and shape were annoying, as the incisive 
edge was directed toward the lower lip. On examination, the 
tooth was firmly socketted, although it was denuded of soft tissue 
on its labial aspect. The bone in this situation had been absorbed 
completely, and the gingival tissue was inflamed. The periodontal 
attachment on the mesial, distal and lingual sides was normal. The 
other teeth were normal, and there was no purulent effusion around 
them (see Figs. 59, 60, 61, 62 and 63). 

The general appearances of these geminated teeth are shown in 
the photographs. The length of the whole tooth was 16 mm., 
its greatest width 3 mm. The width of the attached deciduous 
crown measured 6 mm. The length of the root itself was 10 mm. 
and it was divided longitudinally by an extensive fissure on both 
aspects. The crown of the deciduous tooth was placed at right 
angles to that of the permanent tooth, its concave lingual surface 
directed upward and its labial convex surface downwards. 

(iii) Lacunar and other Dejects 

Definition. — Irregular spaces — not of an interglobular nature — 
which admit of no classification, found in the substance of the 
dentine. 

Etiology. — Congenital defective nutrition or perverted metabo- 
lism of the pulp cells. 

HISTOLOGY 

Dentz, of Utrecht, has observed in the early-erupted teeth of a 
newly-born child certain curious defects, which are undoubtedly 
congenital in origin. Bodies containing apparently six or eight 
nucleated cells, which were closely applied to each other and some- 
what resembling Pacinian corpuscles were discovered in the dentine, 
which measured about 0.25 mm. near the amelo-dentinal junction. 
The spaces were of great size (125/x in length), oval or bilobed in 
shape and outline (Fig. 64). A spiral structure, which might be 
in continuity with the dentinal fibrils could, with difficulty, be 
made out. It is possible that these defects marked a stage in the 
formation of interglobular spaces. 

Ovarian teeth sometimes show areas of dentine where the tissue 
has undergone considerable metamorphosis. In Fig. 65 the tubes, 
which are very much smaller than those of the rest of the dentine 
are running centripetally, not centrifugally, from a point centred at 



5 2 



THE DENTAL TISSUES 




Fig. 64. — Lacunar defects in dentine. (Dentz's specimen. Photomicrograph 

by Howard Mummery.) 




DD 



Fig. 65. — Coronal section of a tooth removed from a teratomatous ovarian 
cyst. Prepared by grinding. Unstained. Magnified 15 times. E. Pigmented 
enamel of defective quality; d. Dentine; d.d. Developmental defects in dentine. 



PATHOLOGICAL CONDITIONS OF THE DENTINE 



53 



the amelo-dentinal junction, below the sulcus of the crown 'which 
intervenes between the two deformed cusps. In colour the abnor- 
mal patch resembles a pale brown, similar to that of the enamel. 
The foundations of the irregularity seem to be matrix of a poor 
quality, myriads of tiny interglobular spaces apparently covering 
it through all its extent. It bears some resemblance in outline to a 
sheaf of wheat. 

The normal dentinal tubes are interrupted in their courses, 
which, however, are resumed in the immediate neighbourhood 
of the enamel. 




Fig. 66. — Structural defect in human dentine. Prepared as in the preceding 
figure. Magnified 40 times, e. Enamel; d. Normal dentine; d.d. Develop- 
mental defect. 

The periphery of this interesting structure displays signs of 
lacunar absorption of the healthy tissue, while two or three large 
spaces, filled with amorphous material, occupy the position of the 
amelo-dentinal junction. The enamel itself is slightly defective 
in structure. 

(iv) Congenital Pigmentation 

Definition. — -Deep brown coloration of the dentinal matrix and 
contiguous cementum of sound {i.e., non-carious) teeth. 



54 THE DENTAL TISSUES 

Etiology. — Some obscure congenital defect. 

Macroscopical Appearances. — When a congenitally pigmented 
tooth is cracked in the jaws of a strong vice, its deeply pigmented 
characters are seen. The staining is uniform, not as in Patho- 
logical pigmentation, as described on p. 76, confined to one part 
entirely, or more pronounced in any particular locality. 

The microscopical examination reveals nothing except pigment- 
ation of the matrix. 

(v) Nanoid or Dwarfed Dentine 

Definition. — Aplasia or agenesia of the dentine of unerupted 
teeth, especially of their roots. It is not a simple atrophy of the 
parts. Atrophy implies a retrogressive metamorphosis occurring 
in tissues or organs which were originally well formed or "in pro- 




m 



Fig. 67. Fig. 68. 

Fig. 67. — Maxillary left first permanent incisor showing nanoid dentine. 
Labial aspect. 

Fig. 68. — Same as the preceding. Lingual aspect. 

portion to the age of the organism well grown." 1 Such a variation 
leads to diminution in size of the organ or structure. While the 
constituent parts shrink variously, through decrease in number and 
size, there is no marked alteration in the minute anatomy or in 
chemical composition. 

Etiology. — An actual immature condition or imperfect develop- 
ment of the roots of teeth may be due to the fact that for some 
unknown reason, teeth have been made to assume abnormal posi- 
tions in their crypts in the alveolar process of the jaws — positions 
in which eruption is impossible. The growth of the roots not being 
required to aid and complete this physiological process may suddenly 
cease. Failure of eruption is caused by failure of root formation, 
or perhaps per contra. The condition occurs in the young — about 
fifteen years. The maxillary incisors may be affected, in which case, 
if the alveolar process in the neighbourhood of the columna naris 
is dense and prominent, nanoid teeth may be suspected. A skia- 
gram will reveal the condition. 

1 Hektoen & Riesman, "A Text-book of Pathology," Vol. i, 1901. 



PATHOLOGICAL CONDITIONS OF THE DENTINE 55 

Macroscopical Appearances. — In the case figured, the actual 
measurements of the crown were 13 mm. in length. The root was 
3.2 mm. on its labial, 6.1 mm. on its lingual aspect. The apical 
foramen was closed and the pulp canal shortened by about one-third 
of the length of the whole tooth. The proper length of the root 
should have been 20 mm. or more. The microscopical structure 
of nanoid dentine calls for no remark. 

(vi) Vascular Canals 

Definition. — Large, uniformly sized channels in the tissue passing 
from cementum to pulp, and containing, post mortem, a thrombosed 
blood-vessel. 

Etiology. — The persistence at the periphery of the pulp of a large 
vessel or bundle of capillaries would probably give rise to this 
abnormality. 

Vascular canals are occasionally associated with dilaceration 
of the teeth. 

HISTOLOGY 

Running from the pulp to the periphery, and piercing both dentine 
and cementum, the channels pass, sometimes sending out a branch 
or tributary which may end in a cul-de-sac. But the termination 
of the main canal itself is on the inner surface of the periodontal 
membrane. 

A small artery with its attendant vein may be found in situ, 
the former empty of its contents, the latter sometimes blocked by 
means of a thrombus. 

The condition is unconnected with cemental hyperplasia, or any 
of those pathological changes which sometimes occur round and 
about the pulp canals. 

The presence of vascular canals in the hard tissues of the roots 
of teeth constitutes a grave source of danger if some devitalising 
agents happen to be used in connection with diseases of the pulps 
of teeth so affected. The condition cannot be diagnosed till after 
the removal of the tooth. 

B. — ACQUIRED DISEASES 

(vii) Absorption 

This common pathological condition may take place from without 
or from within, i.e., from the cemental or the pulp side. 



56 



THE DENTAL TISSUES 



Definition. — The removal of dentine, as part of a pathological 
process — in contradistinction to the physiological absorption of 
roots of deciduous teeth — not due to caries. 

Etiology. — Chronic inflammation of the pulp or periodontal 
membrane from whatsoever cause may induce certain changes 
in the cells of the soft tissues, which, unduly stimulated, remove 
the hard parts in their immediate proximity. The absorption is 
probably due (i) to the activities of multi-nucleated giant cells 
(osteoclasts) as physiological factors, because these bodies, although 



I 



sc- 




HC/ '% ' * 






CH 



Fig. 69. — External absorption of dentine. Shows D. Dentine; s.c. Normal 
structureless cementum; h.c. Hyperplasic cementum. {From a section in the 
collection of A. W. W. Baker.) 

they have never been observed in the pulp tissue, nor do they exist 
in the inner aspects of the periodontal membrane, yet are common 
enough in the bay-like recesses of the alveolar bone. The absorption 
may also, most probably, be correctly ascribed (ii) to the presence 
of absorption-leucocytes or phagocytes brought into physiological 
contact with the hard parts by means of the small cell infiltration 
of the soft tissues, the result of the inflammation. 

Acute inflammation of the periodontal membrane accompanied 
by suppuration, as a result of impaction of a contiguous tooth may 
also induce absorption, probably (iii) by the action of acid pus 
merely dissolving away the lime salts from the organic matrix 



PATHOLOGICAL CONDITIONS OF THE DENTINE 57 

near the seat of lesion, a pathological action resembling that which 
occurs sometimes in absorption of bone viz., halisteresis. 

Pathologists agree that in the case of bone, pathological absorp- 
tion is produced, either by (a) the agency of osteoclasts ("lacunar 
absorption"); {b) decalcification ("halisteresis"); or (c) granulation 
tissue, through the medium of certain round cells which possess a 
phagocytic function. It is exceedingly likely that these, or similar 
agencies, can produce like results with regard to the absorption 
of cementum and dentine. 

Macroscopical Appearances. — When the apex or side of the root 
is affected, a roughening of the surface results. Thus "needle- 
point" absorption is common on the apex of the root. 

No pigmentation occurs, and no caries. 

Secondary Changes. — If the inflammation undergoes resolution, 
which it most generally does, organisation supervenes on an attack 
of chronic inflammation, and the cementum, more or less lacunated 
and laminated on the one hand, or a cementum-like substance, which 
has been termed "osteodentine" — a bad appellation — or even bone, 
well-organised and unmistakable — on the other hand, may be 
produced. 

HISTOLOGY 
(a) External Absorption 

In the belief that osteoclasts properly so constituted do not exist 
in the pulp or the innermost zone of the root membrane, it is not 
surprising to find absence of Howship's foveolae. It is true that 
more or less festooned outlines are met with in places, but they are 
nothing like those found in the physiological absorption organ of 
deciduous teeth or on the surface of the shafts of bone. 

In this way, therefore, in the case of external absorption, a por- 
tion of the external surface of the dentine loses its normal, outline, 
a break occurs in its continuity, the breach of surface being filled 
with irregularly-developed cementum. It may be hollowed out 
sometimes to any depth, or it may be absorbed in a straight line, 
as in a specimen of Baker's, of Dublin (Fig. 69). 

Specimens of the first condition show the following details: The 
normal cementum and granular layer have disappeared; no sharp 
line of demarcation intervenes between the normal and the diseased 
parts; the dentinal tubes are cut off squarely with their course, and 
■ — a point of some interest — cemental lacunae, large and confluent, 



58 THE DENTAL TISSUES 

and not possessing prominent canaliculi are placed, in no great 
numbers, immediately on the cut ends of the tubes. Many la- 
cunae are of the abrachiate variety. 

Both kinds of absorption may be illustrated by Dr. A. W. W. 
Baker's example. He describes it by saying 1 that "two-thirds of 
the circumference of the tooth show evidence of inflammatory 
action of a more or less chronic nature, that is to say, there can be 
traced zones of the cementum where the root membrane was in a 
healthy condition and deposited normal cementum, then periods 
where the root membrane became actively inflamed and absorption 

took place The remaining third of the circumference 

of the root showed absorption by abscess of a severe and extensive 
nature, as not only the cementum but also the dentine was involved 

and absorbed The distinct band of new tissue is here 

very well marked, and at first sight seems as if the section were folded 
upon itself" (see Fig. 69). 

The writer considers that in this case osteoclasts are the predomi- 
nating factors of the absorption. Sir John Bland-Sutton, in his 
"Introduction to General Pathology," p. 124, 1887, says: "In the 
giant cells (formed by the fusion of leucocytes, which have migrated 
from the new capillary blood-vessels of the granulation tissue of 
inflammation) we have the counterpart of the fusion of phagocytes; 
the large multinuclear osteoclasts seen in places where vertebrate 
bones and teeth are undergoing absorption, must also be placed in 
the same category." 

If this interpretation is correct (and modern research would 
seem to confirm it), it is not difficult, it must be confessed, to com- 
prehend not only how the new formation of osteoblasts in the mem- 
branes bordering the periphery of the cementum arises, but also in 
what manner their transformation into osteoclasts, and ultimately 
lacunar corpuscles, is brought about. 

G. V. Black {op. ciL), speaking of absorption, states his opinion 
that the physiological absorption of deciduous teeth is precisely 
the same plan by which the roots of permanent teeth are occasion- 
ally, pathologically absorbed, either in part or completely. Never- 
theless, though this writer evidently believes that cementum and 
dentine are both absorbed by means of osteoclasts, nowhere does 
he make a definite statement to that effect, nor do his figures show 
them. Indeed, while in every case his drawings of absorbed den- 

1 "Advanced and Retarded Dentition." Journal British Dental Association, 
p. 432, 1902. 



PATHOLOGICAL CONDITIONS OF THE DENTINE 59 

tine and cementum exhibit outlines somewhat simulating those of 
the foveolae of Howship, he is careful to avoid the pictorial expres- 
sion of an osteoclast — or, as some would call it, a cementoclast — 
filling up the excavations. One illustration exhibits particularly 
well these giant cells on the alveolar side of the root membrane, 
but they are omitted on the other. 

Unique Extensive Absorption 

A singularly instructive case of the absorption of the roots of 
many of the permanent teeth in one mouth which came under the 
personal notice of the author may be quoted. The case is possibly 
unique; and, possessing very extraordinary characteristics, its 
aetiology is so difficult to determine, and the actual pathological 
phenomena which it exhibits so full of significance, that, as a 
result, it is raised to a high level of interest and importance. 

A man aged 44, has been under observation for a number of years, 
his mouth presenting very varied aspects as an infection advanced. 
Family History: The mother is edentulous: the father practically 
so. A sister, aged 25, has the right maxillary canine still unerupted, 
the cusp just appearing through the gum. There is no purulent 
effusion round her teeth. Past History: For fourteen years the patient, 
then being aged about 29-30, had a swelling under the mandibular 
first molar, which was very carious. Extraction under an anaes- 
thetic failed to remove the tooth entirely. On examining the mouth 
at the time of operation, it was discovered that all the other molars — 
the upper and lower third molars not included — had their crowns 
only slightly erupting through the gum, although the premolars 
and incisors were fully developed and occluded in a normal manner. 
As the conditions were extremely uncommon, and as the swelling 
" did not go down," the patient was sent to the consulting surgeon of 
a Hospital, who, anxious to await further developments and give 
Nature an opportunity of correcting the abnormal state of the mouth 
and jaws, merely ordered an "ointment" for external use. 

When the dental surgeon next saw the case an abscess had opened 
which would not heal. The patient was thereupon sent to the 
Hospital, and the surgeon for the day endeavoured to remove the 
roots of the tooth, but failed. He was then seen by the dental 
surgeon of another Hospital, and again operated upon, but with no 
greater success. Some long time afterwards the patient told his 
private practitioner that a piece of bone, or "something like it," 



60 THE DENTAL TISSUES 

came through the opening on the face, and then the abscess healed. 
All the partially-erupted molars except one have been shed spon- 
taneously — i.e., become loose, and been removed from the mouth 
by means of the fingers, and are in a more or less similar condition, 
showing signs of extensive absorption. The crown of a third right 
maxillary molar was, in December, 1908, felt with an explorer, 
buried in the jaw, the tooth itself erupting and spontaneously 
becoming shed by absorption of its roots, six months later. 

The patient himself told the author that, with jaws closed, the 
fingers could be inserted between the occlusal surfaces of the molar 
teeth on both sides, showing that they never occluded in the normal 
manner, a space of one-sixteenth or one-thirty-second part of an 
inch intervening. For fifteen months there had been a certain 
amount of discharge of pus and swelling of the gingival tissues. 
Trismus was present at times to a slight degree, and the patient also 
suffered greatly from insomnia. The maxillary right canine was 
sound, but had an abscess associated with it, and was therefore some- 
what loose. Having meanwhile been crowned, it is now quite firm. 
Practically there has been no pain throughout the whole course of 
the disease, the discharge of pus from the back of the mouth being 
the most prominent symptom. There has been no tartar to speak 
of, and the general condition of the oral mucous membrane is, and 
has been, fairly good. The patient had rheumatic fever when he 
was aged $5, is somewhat delicate, and probably neurasthenic. 

At the time of examination it was noted that the mouth is clean 
and well cared for. Tartar is absent round the necks of the remain- 
ing teeth. Great absorption of the alveolar processes has occurred. 
Of all the maxillary teeth, the two canines, the second left premolar, 
and the root of the second right premolar remain, one of the former 
having been crowned. The latter, however, shows signs of chronic 
inflammation of the periodontal membrane especially on its dis- 
tal aspect, probably through loss of bone-substance of the jaw. 
The mandibular alveolar ridges are flat; the teeth remaining in 
situ are the two second incisors, the canines, the two first pre- 
molars, and the left second premolar. The other teeth have been 
extracted from time to time, through loosening on account of the 
alveolar changes. Eruption of the right mandibular third molar 
is now taking place. 

Macroscopical Appearances. — (i) Left mandibular second molar: 
On the occlusal surface of the crown there is a rounded cavity occu- 
pying the site of the postero-mesial cusp, its greatest diameter being 



PATHOLOGICAL CONDITIONS OF THE DENTINE 6 1 

4.5 mm. and shortest 3.5 mm. Extending downwards and back- 
wards and towards the lingual side, it avoids the pulp chamber and 
opens externally below the cervical margin on the posterior surface, 
by a small pin's head point, on the lingual surface by two sinuous 
perforations (Fig. 70), and in the radicular region in a large irregular 
shallow excavation, 9.5 mm. in length. The greatest area of ab- 
sorption is found on the mesial aspect (Fig. 71). Here the enamel is 





Fig. 70. Fig. 71. 

Fig. 70. — Left mandibular second molar: lingual aspect. 
Fig. 71. — The same tooth: mesial aspect. 

unaffected, but immediately below, a large loss of dentine and ce- 
mentum has taken place, measuring 12 mm. long by 8 mm. wide. 
The cementum is hyperplasic, the pulp cavity not exposed. The 
length of the tooth is 21 mm. There is no transparency of the roots, 
which are confluent through the hyperplasia of the cementum. 
One minute apical foramen can be detected. 






Fig. 72. Fig. 73. 

Fig. 72. — Right maxillary third molar: distal aspect. 
Fig. 73. — The same tooth: buccal aspect. 

(ii) Right maxillary third molar: Tne crown is flattened ?nte'. - c- 
posteriorly. A large amalgam fillihgj situated on the buccal' surface, 
fills the site of the antero-external and intero-inte.cna] cusps. A 
discoloured patch of enamel is seen on" the free edge." The' mesial 
surface of the root is discoloured and presents three small hollows. 
A large area of absorption is observed on the' distal and buccal 
surfaces (Figs. 72 and 73), the former being entirely excavated ex- 
cept at the extreme apical region. The roots are very hyperplasic 



62 THE DENTAL TISSUES 

and reflected backwards. The apical foramina are closed and invisi- 
ble. The whole of the palatine root has disappeared, the consumed 
surface measuring 12 mm. by 6 mm. by 5 mm. The length of the 
tooth is 21 mm. 

(iii) Right maxillary second molar: The crown is roughly quadri- 
lateral in shape. There is a gold filling on the morsal surface at 
the part between the antero-external cusp and the ridge joining 
the antero-internal and postero-external cusps. The crown is 
otherwise free from caries. The buccal roots are united together, 
rough, and greatly enlarged by hyperplasic cementum, the surface 
being very slightly attacked by the destructive process. The apical 
foramina are invisible. The palatine root is largely reduced in 
length by the absorption, slightly near the cervical region on the 





Fig. -4- Fig. 75. 

Fig. 74. — Right maxillary second molar: distal aspect. 
Fig. 75. — The same tooth: lingual aspect. 

lingual aspect, more so at the apical portion. The length of the 
tooth to the apices of the buccal roots is 18 mm., the palatine 
root measuring 16 mm. (Figs. 74 and 75). 

(iv) Left maxillary second molar: The crown is non-carious. There 
is a tendency for it to become oblique in outline, its fissures and pits 
being pronounced. The enamel is entirely free from disease. The 
buccal roots are confluent, but discoloured. There are cavernous 
openings on all the surfaces, the greatest being over the outermost. 
It covers an area of 42 sq. mm. (Fig. 77). The pulp is not pene- 
trated. The palatine root, exceedingly honeycombed, is reduced in 
. length. , There, are. sevoral exciescen.eps of hyperplasic cementum on 
th£ distal i-u since, .of the -body. cf -.the tooth, at the junction of the 
roots (Fig' $(■) ..-.The length of the tooth, on its buccal aspect, is 
20.5 m mi, and 17.5. -nm., en, lingual side. 

(v) Left max,illary third molar: The crown here is non-carious, 
but* flattened frora before backwards. Enamel, while being dis- 
coloured, is intact, except undergoing a small amount of loss on the 
mesio-lingual side. Two small deep pits are observed on the buccal 



PATHOLOGICAL CONDITIONS OF THE DENTINE 



63 



aspect. All three roots are united and thickened. The buccal 
roots on the free surface exhibit an absorption area 7 mm. and 4 mm. 
across the widest and narrowest diameters respectively, while dis- 
tally, an irregularly formed cavity is seen, and mesially, two small 
depressions, closely situated. The palatine root displays the rav- 
ages of the disease best of all. On the mesial aspect the dentine and 
pementum, covering a superficies of 13 mm. by 7.5 mm., have been 





Fig. 76. Fig. 77. 

Fig. 76. — Left maxillary second molar: distal aspect. 
Fig. 77. — The same tooth: buccal aspect. 

removed (Fig. 79). The pulp is here apparently invaded. The 
length of the tooth averages 19.5 mm. 

The edges of the excavations of all the teeth, on examination with 
a lens, are, generally speaking, rounded, everted, and smooth when 
dentine and cementum are destroyed; when enamel is involved, 
sharp and well defined. They nowhere exhibit the naked-eye ap- 





Fig. 78. Fig. 79. 

Fig. 78. — Left maxillary third molar: mesio-lingual aspect. 
Fig. 79. — The same tooth: mesial aspect. 

cearances of having been produced by osteoclasts, as Howship's 
foveolae are probably entirely wanting. 

In reference to the present case several facts stand out strikingly. 
First, the molars erupted most imperfectly. Some unknown rea- 
son lies at the back of this. The ordinary physiological forces 
were not only retarded but in abeyance. They cannot have been 
affected by the deciduous dentition, as the permanent molars, 



64 THE DENTAL TISSUES 

of course, come up behind the milk teeth. There must be some con- 
stitutional disturbance at work, acting in an extraordinary manner, 
in producing this grave defect in the assumption of their normal 
position in the dental arch of the masticatory organs. The history 
of the right maxillary third molar shows that its life duration only 
extended over about seven or eight months. There is complete 
absence of any of the usual causes of delayed or anomalous eruption 
of teeth, and its cause in the present case remains a mystery. Sec- 
ondly, the molars were not devitalized — i. e., " dead." In each, except 
one, the pulp was alive and protected by its wonderful physiological 
resistance from the attacks of the great pathological processes 
going on outside. Thirdly, the disease, whatever was its nature, 
was practically confined to the molar region. None of the other 
teeth were similarly affected. This is the most inexplicable part 
of the case. That the infection, if it was induced by pyogenic 
micro-organisms in the first place, should limit itself to the posterior 
parts of the oral cavity is truly surprising. Fourthly, the presence of 
pus in large quantities at times was a prominent sign and, no doubt, 
associated with the granulation tissue produced around the roots 
of the teeth. Fifthly, the molars, having shared a common affec- 
tion which was spread over a considerable number of years, be- 
came shed spontaneously. 

It is difficult, as has already been pointed out, to decide on the 
aetiology of this absorption. The author puts forward his opinion 
as follows: There were two factors probably which played an im- 
portant predisposing part in the production of the disease — viz., 
(1) the disuse of the teeth through lack of occlusion, and (2) consti- 
tutional debility. The probable sequence of events would be, a 
bacterial invasion of the periodontal membranes of the functionless 
molars, setting up a chronic periostitis which resulted in organiza- 
tion and hyperplasia of the cementum. The bacterial influences 
not having been withdrawn, the chronic periostitis was further 
changed into granulation tissue which, occupying the sockets of 
the teeth, by means of small round cells possessing phagocytic 
properties, removed not only the alveolar bone but almost equally 
the dentine and cementum of the teeth. 

(J3) Internal Absorption 

There are evidences in absorption from the pulp side that ab- 
sorption-leucocytes (osteoclasts) perform the functions of removal 



PATHOLOGICAL CONDITIONS OF THE DENTINE 65 

of the dentine, and traces of the effects of chronic inflammation 
of the pulp are not wanting. Internal absorption is accompanied 
by obliteration of the original outline of the root canal, the resulting 
cavity being irregular in contour and enlarged to a varying degree. 
The more or less semilunar excavations may be confined to one or 
more portions of it, and produce subsidiary canals which run at 
angles — acute, right, or even obtuse — to the original pulp chamber. 
Caush 1 has well investigated this subject. He writes: — "These 
semilunar excavations vary much in size as well as in number, 




Fig. 80. — Internal absorption of dentine, with deposition of cementum-like 
material in the pulp cavity. Magnified 45 times. (From a section in the col- 
lection of Douglas Caush.) 

varying from a single light dip or depression, as found in the earlier 
stage, to the numerous excavations producing the complex and 
irregular outline as seen in the advanced stage." 

Very often this removal of tissue is followed by deposition of 
dense osseous material, a sharp line of distinction between the new 
and the old marking off this new development (Fig. 80). The 
adventitious structure is devoid of tubules — thus differing from many 
forms of adventitious dentine — and is, therefore, not dentine; but 
it is composed of lacunae and canaliculi imbedded in a granular 

1 Trans. World's Columbian Dental Congress, p. 114, el seq., 1894. 
5 



66 THE DENTAL TISSUES 

matrix, as in hyperplasic cementum. The lacunae vary in number, 
size and position: thus they may be placed very closely together, 
or scattered throughout the mass. In the former they possess 
short, in the latter elongated canaliculi. 

In explanation of the modus operandi by which these changes 
are wrought, Caush describes alterations in the shape of the odon- 
toblasts, which, under the influence of hyperaemic or inflammatory 
conditions of the pulp undergo sub-division by mitosis. The cells 
in contact with the dentine begin to absorb that tissue, their func- 
tion being more rapidly carried on, and far more reaching in its 
effects, if the dentine forming the boundary of the root canal hap- 
pens to be somewhat poorly calcified or developmen tally defec- 
tive. Caush inclines to the belief that the odontoblasts can be- 
come converted into osteoclasts, which, later on (that is to say, when 
their absorptive energies are concluded), become again changed to 
formative cells and manufacture the osteoid cementum-like tissue. 
He, however, gives no drawing of giant cells. They are not re- 
quired: the mere effect of the inflammatory products themselves, 
viz., the phagocytic leucocyte, being sufficient, per se, to produce 
the excavation. 

In this connection, an instructive case, described by F. J. Bennett 
in The Dental Record for June, 1899, may be quoted, summing up, 
as it does, very succinctly the salient pathological features of inter- 
nal absorption. He writes: — 

"Whilst examining a collection of old teeth, the following speci- 
men came under my notice, which is of interest, partly from its 
presenting a pathological condition of uncommon degree, and 
also as illustrating the steps employed by nature for the removal 
and repair of injured tissues. 

"The tooth was a well- formed lower molar which had been at- 
tacked by caries upon the proximal surface at its junction with the 

cervical region On section, the pulp canals were found to 

be empty, and showed no signs of having been treated. The surface 
of the roots presented the usual appearance of long continued 
chronic inflammation, being thickened with patches of porous light- 
coloured cementum, and having vascular canals here and there 
penetrating the substance of the tooth. Indeed, it was due to one of 
these apertures of unusual size, and with rust coloured margins, that 
attention was first called to the case. Situated midway between the 
neck and the apex of the anterior root, it was found on section to 
terminate in two large cavities representing the pulp canal, which at 



PATHOLOGICAL CONDITIONS OF THE DENTINE 67 

this point had become extended in various directions greatly beyond 
its original size. 

''Under the microscope, it was found that the cavities and the 
channels leading to them were everywhere attacked by absorption, 
presenting the conspicuous lunated outlines known as Howship's 
foveolae or lacunae. The margins were also stained with the rust 
colour of haematin crystals. 

"The cementum covering the root was thickened, and towards 
the apex there were signs of alternations of absorption and 
deposition. 

"This direct and extensive attack upon the interior of the tooth 
suggests the existence of some source of irritation within the root 
injurious to the surrounding cementum and periosteum; and fur- 
ther, that it was for the removal of this source of mischief that the 
process of absorption was set in action. 

"Quite recent investigations have shown that leucocytes are the 
essential agents in the process of absorption, the mass of highly 
vascular granulation tissue found lining these absorption cavities 
being the means by which the absorption cells are brought into actual 
contact with the affected tissue. These absorption leucocytes or 
phagocytes, migrating from the capillary vessels of the granulation 
tissue singly, or uniting together to form giant cells, attack and 
take into their interior the particles to be removed. 

"The recognition of the nature of the osteoclasts as originating 
in the leucocytes may be considered as a great step in advance, 
as it leads one to regard many of the processes at work in the hard 
and soft tissues as essentially similar in nature. According to 
Ziegler, ' Recent researches into the absorption of bone appear to 
place it on a level with absorption of other tissues, and to view them 
all from the same standpoint.' 1 

"Although it is common in the soft parts and in bone to find 
diseased tissue becoming detached in the form of a slough, or of a 
sequestrum at its line of junction with the healthy tissue, by the 
interposition and activity of the phagocytes, this is possible only in 
tissues possessing a vascularity sufficient for the conveyance of the 
cells to this situation. The cementum, however, possesses no such 
system of capillary vessels throughout its substance for the circula- 
tion of blood cells, as in the case of the Haversian canals of bone; 
consequently this method of removal of diseased tissue by exfolia- 
tion does not occur. The process adopted in this instance is essen- 
1 Ziegler's "General Pathology and Anatomy," p. 160. 



68 THE DENTAL TISSUES 

tially similar to that occurring in the molecular absorption, or true 
caries, of bone. The phagocytes channel a passage .... the 
channel becomes lined with the granulation tissue which penetrates 
the dentine and ultimately spreads itself over the surface of the root 
canal, allows the migrating cells to absorb and remove the diseased 
dentine down to the surface of the living cementum. 

" I am inclined to regard this specimen as illustrating a conserva- 
tive aim on the part of Nature. The form of the absorption is dif- 
ferent from that usually seen in permanent teeth which are being 
shed. In the latter case, the root is either shortened or reduced in 
circumference, and the cementum is equally — if not more — absorbed 
than the dentine. In this specimen the struggle to maintain the 
cementum in an efficient condition is exemplified by the patches of 
removal and redeposition of cementum which occur in various 
places. 

"I have not met with an instance in which repair has followed to 
such an extent that the root cavity comes to be again occupied 
by fresh nutrient tissue, but a remarkable specimen described and 
figured by Salter 1 inclines me to the belief that this may sometimes 
take place. In this case well-formed bone with Haversian systems 
had come to occupy a large portion of the pulp cavity, which latter 
bore traces of previous lacunar absorption. The pulp cavity had 
three circular apertures entering it from the external surface a 
little below the neck, and these were also lined by bony tissue. The 
ossification of granulation tissue in my own specimen would probably 
have led to similar appearances." 

True bone, identical with the compact variety, may fill, under 
rare conditions, all the interspaces of internal absorption of dentine. 
In such cases, the Haversian systems are large, the lacuna? numerous, 
and the osseous lamellae pronounced, while large irregular spaces 
probably contain in the recent state portions of the included pulp. 
Four well-authenticated specimens are on record, one described by 
Messrs. John Ackery and J. F. Colyer (Trans. Odonto. Soc. of 
Great Britain, p. 66, 1893), a second by Salter, a third by Tomes 
(Trans. Odonto. Soc. p. 178, 1899), and the last now published with 
a photomicrograph for the first time. 

The first case was as follows: — 

A partially-erupted premolar in the mouth of a patient of 33 
years of age, exhibiting caries, was removed on account of irregu- 

1,1 Dental Surgery and Pathology," p. 79. 



PATHOLOGICAL CONDITIONS OF THE DENTINE 69 

larity in position. The root was only two-thirds completed. It was 
difficult to say whether this diminution in size was due to arrested 
development or absorption; but the latter was the more plausible 
theory. 

"The transverse sections showed that the dentine contained 
in its midst true bone. In one, taken near the crown, two or three 
small canals were seen containing tissue exactly like bone. In a 
lower section, a large portion of the dentine had been replaced by a 
tissue very irregular in character, but being, in places, of a distinctly 
osseous character. To the side of this, but yet separated from it, 
was another oval space containing distinct osseous tissue. In a 
third section these two spaces had fused together, and the first had 
progressed much further into the dentine. The tissue towards the 
pulp chamber still retained the irregular character already spoken of, 
but in the portion most distant from the pulp there was distinct 
osseous tissue with well-marked Haversian systems. The next 
section showed a still greater portion of the dentine replaced by 
true bone, the irregular tissues only being apparent in that part 
nearest to the pulp chamber." 

Salter's specimen 1 was a molar having three canals piercing 
the cervical region just below the edge of enamel. Vertical sec- 
tions were made, and revealed the following: — The substance around 
the canals was yellower and more translucent than the normal den- 
tine, extended for some distance into the crown, and down the side 
of one of the roots. Examination with the microscope proved this 
to be cancellous bone in all its salient features — small, uniformly 
sized and regularly arranged lacunae, with few small canaliculi, and 
even and regular lamellae placed parallel with the outlines of the can- 
celli. The line of demarcation between bone and dentine was 
strikingly sharp, though here and there isolated patches of the 
latter were inextricably mixed up with the former. 

For the last example, the author is indebted to the courtesy of 
Mr. H. R. Pring. A maxillary first incisor from an old patient 
became loose, and on removal was seen to have an absorbed root. 
Median coronal sections, viewed microscopically from within, 
gave the appearances of a spicule of bone in dentine. Histolog- 
ically, the tissue was true compact bone, as is seen in the photo- 
micrograph (Fig. 81). It requires no special description. 

' Op. tit. p. 97. 



7° 



THE DENTAL TISSUES 




Fig. 8i. — Vertical section of human incisor with internal absorption of dentine, 
and deposition of true compact bone. Prepared by grinding. Stained with 
impregnation by coloured collodion. Magnified 50 times. D. Primary dentine; 
a. Area of absorption; b. Compact bone; Si. Large Haversian canal; S2. 
Small Haversian canal; c. Hyperplasic cementum. 



PATHOLOGICAL CONDITIONS OF THE DENTINE 



71 



(viii) Adventitious Dentines 

Definition. — Tissue of a pathological nature which has been 
added, in the course of dental caries, and in erosion, to the primary 
or first-formed dentine. 

Etiology. — Inflammatory conditions of the pulp, the result of 
penetrating or deep caries of the dentine produces stimulation of 



D 




Wif :'; 




e.< 



?f\* 



3 



* 



i 



A 




t 



£ 



** 



,v 



E 



■ ki..r ;: it! - 



Fig. 82. — Areolar adventitious dentine. Magnified 500 times. D. Primary 
dentine; a. Areolar spaces filled with detritus; f. Connective-tissue fibres. 

the peripheral cells — not odontoblasts — of the pulp, which then 
proceed to lay down a new form of dentine. 

Macroscopical. Appearances. — None. 

Secondary Changes. — Certain varieties may, under the influence 
of advancing caries, become infected with micro-organisms. Of all 
the varieties, except the hyaline, to be presently noted, each is 
liable to this infection. 

HISTOLOGY 

Microscopically considered, there are five varieties: — (a) areolar, 
(/?) cellular, (7) fibrillar, (6) hyaline, and (e) laminar. 



72 



THE DENTAL TISSUES 



(a) Areolar 

Its general characteristics resemble those of dentine filled with 
interglobular spaces (Fig. 82). It intervenes, as a tissue of 
repair, between a carious cavity and the pulp. Modified tubules 
may or may not accompany it. When they do, they are sparingly 
filled with round and rod-shaped micro-organisms, enlarge greatly 
as they extend inwards, and terminate with wide open mouths at 
their pulpar extremities. Probably this widening of the tubes is 
due to partial softening of the intertubular matrix. 




Fig. 83. — Areolar adventitious dentine. Magnified 250 times, d. Primary 
dentine; A. Areolar dentine; P. Pulp tissue. 

It forms a thick sheet of hard material, devoid of ordinary dentinal 
tubules, being constructed of partially-fused calcospherites in the 
ordinary way. Its free edge is covered with round cells. Hyperae- 
mia of the pulp accompanies its formation. It is the most com- 
monly recurring of all kinds, and may be associated with the fibril- 
lar variety, as in the foregoing illustration. 



(|8) Cellular 

This is probably the same as that just described, with the addition 
of the presence in the matrix, of cells which may be fusiform or round. 



PATHOLOGICAL CONDITIONS OF THE DENTINE 73 

The former are common when an areolar condition is present, the 
latter when a hyaline matrix invests certain round or spindle cells 
of the pulp. They are caught unawares, so to speak, in the osseous 
flood poured out round and about them. 

The cells vary very much in size, the innermost being six or eight 
times as large as the smaller ones near the dentine. Towards the 
former side, rows of encapsuled cells may exist, some being multi- 
nucleated as if they had undergone mitosis. The surrounding pulp 
tissue, in immediate relationship with the new deposit, consists 
mainly of fusiform cells arranged in bundles interspersed with small 




Fig. 84. — Cellular adventitious dentine. Magnified 250 times, n. Nuclei of 

encapsuled cells; M. Matrix. 

round cells, the former possessing oval and the latter rounded 
nuclei. 

(7) Fibrillar 

Fibrillar adventitious dentine bears a close resemblance to ordinary 
dentine; but the tube-like structures are much finer and less regular 
than in ortho-dentine. It is extremely probable, though not 
admitting of easy demonstration, that the lines are actually con- 
nective tissue fibres, and not hollow tubes. 

The dentine is deposited in layers, and presents a characteristic 



74 



THE DENTAL TISSUES 



fibrillar structure. It is observed in cases of chronic caries. On 
the border line of the hard and soft parts, the connective tissue 
formation of the dentine is strikingly established. 



(5) Hyaline 

This kind of new dentine has, as its favourite site, the base of a 
carious excavation into the pulp cavity. It may be irregularly 
rounded in shape. Its structure, in some places, conforms to that 
of a more or less homogeneous ground-glass-like matrix similar to 




Fig. 85. — Fibrillar adventitious dentine. Magnified 250 times. D. Primary 
dentine; f. Fibrillar dentine. 

that of hyaline cartilage; in others, it has a distinctly granular or 
fibrous appearance. 

Distributed at its margins, cellular adventitious dentine may be 
often observed. 

It is associated with chronic inflammation of the pulp, especially 
when this has fungated through the opened pulp chamber, granu- 
lated and produced a soft tumour in the carious cavity of the crown 
of the tooth — productive inflammation of the pulp, formerly called 
"polypus." 



PATHOLOGICAL CONDITIONS OF THE DENTINE 



75 




u 




Fig. 86. — Hyaline adventitious dentine. Magnified 250 times, h. Hyaline 

dentine; p. Pulp tissue. 




Fig. 87. — Laminar dentine. Magnified 250 times. d. Primary dentine; 
l. Laminar dentine; p. Pulp tissue. 



76 THE DENTAL TISSUES 

(e) Laminar 

The variety thus described also may be associated with it in 
laminated form, in which patterns simulating pulp nodules appear. 
In fact, it is possible that these bodies are metamorphosed pulp 
nodules. 

(ix) Pathological Pigmentation 

Pigmentation of the dentine may be partial or complete, pink 
or green of varying shades or degrees. It never exists alone, the 
cementum and very rarely the enamel sharing its staining. 

Definition. — A permanent coloured condition of the dentine. 

Etiology. — Never a congenital defect, it differs from like conditions 
of enamel, in the fact that it may be produced in one of two ways, 
each of which leads to different results. Thus: If, as a consequence 
of a blow on, or damage to, the pulp through mechanical or chemical 
agencies, an artery is ruptured, there may be, under favourable 
circumstances, an escape of oxyhaemoglobin into the neighbouring 
structures. The colouring matter of the blood permeates the 
dentinal tubules, and sets up both superficial and deep areas of 
hematogenous pigmentation. Here the colour is pink. 

In the second case, staining of a green character is due to the 
discoloration of the tissues, either through death of the organic 
parts, or through the introduction into the root canals of some 
filling material, as is induced by some kinds of amalgam, especially 
those, it is believed, which contain salts of copper. 

Precisely how this is brought about is unknown. 

Macroscopical appearances are unnoticed till the tooth has been 
removed from the mouth. The cementum is stained, and on 
breaking the dentine in a vice it also is found coloured through- 
out. 



(x) Senile Dentine 

While enamel, once fully formed, is incapable of undergoing any 
further changes incidental to old age, dentine, especially in the 
radicular regions of teeth, is often affected by them. 

Definition. — The dentine of old age. 

Etiology. — The cause may be attributed to a weakened or dimin- 



PATHOLOGICAL CONDITIONS OF THE DENTINE 



77 



ished nutritive supply, producing trophic changes primarily in the 
pulp and secondly in the hard tissues. 

Macroscopical Appearances. — The dentine and cementum are 
rendered yellow or brown, and the apices of the roots become semi- 
transparent, or in long-continued cases quite transparent. 

Secondary Changes. — None. 

HISTOLOGY 

The matrix is granular; the tubes are not narrowed, but are 
apparently absent. This is not, however, the case; an internal 





\' 



Fig. 88. — Senile dentine. Magnified 45 times. D. Primary dentine; s. Pri- 
mary dentine which has undergone senile changes; P. Calcified pulp. 

change has made them by transmitted light assume or approximate 
to the same refractive index as the matrix. They cannot be stained. 
Little is known with certainty as to what has occurred, but it is 
extremely likely that they have become occluded throughout their 
extent, wholly or partially, by a deposition of calcified material 
within their walls. They are no doubt solid, and incapable of 
transmitting sensations to the pulp. 

The tubules and their contents were believed to undergo fatty 
degenerative changes by Heider and Wedl, who, in their well- 



78 



THE DENTAL TISSUES 




Fig. 89. — Vertical section from a senile tooth. Prepared by grinding. Un- 
stained. Magnified 35 times, e. Enamel; d. Primary dentine; c. Calcified 
pulp. (From a specimen in the collection of G. W. Watson.) 



PATHOLOGICAL CONDITIONS OF THE DENTINE 79 

known Atlas, in Fig. 75, describe a varicose condition of the tubules. 
The enlargements contained fatty shining granules, arranged in 
pater-noster-like rows. They were associated with free fatty drops. 

Accompanying senile dentine, the pulp cavity is generally filled, 
as in Figs. 88 and 89, with a dense deposit of secondary dentine, 
and there is nearly always present a certain amount of cemental 
hyperplasia. 



CHAPTER III 
THE PATHOLOGICAL CONDITIONS OF THE CEMENTUM 

Microscopical Elements in: — (i) Cemental nodules; (ii) Ankylosis; 
(iii) Hyperplasia; (iv) Senile cementum. 

A. — DEVELOPMENTAL AFFECTIONS 

(i) Cemental Nodules 

Definition. — Sessile circumscribed tumours of the cementum, which, 
in man, are extremely rare. They may be called "cementomata." 

Etiology. — They are produced by local development and calcifica- 
tion of the osteoblasts of the periodontal membrane. 

Macroscopical appearances are the same as in enamel. 

Secondary Changes. — None. 

HISTOLOGY ] 

The dentine is normal and the granular layer of Tomes presents 
no changes. 

The cemental matrix is structureless, and extends as a thin layer 
over the dentine. 

The neoplasm is made up of arcuate bands of matrix with laminae 
and canaliculi. Fairly numerous, the first formed layers are dense 
and more lacunated than the youngest portion. The inflammation 
of the periodontal membrane has undergone resolution, indicated 
by the formation of the homogeneous layer of cementum most 
externally. The photomicrograph, Fig. 90, shows a nodule which 
existed at a locality 6 mm. below the cervical edge of a mandibular 
molar. The specimen is believed to be unique. 

B. — ACQUIRED DISEASES 

(ii) Ankylosis or Synostosis 

Definition. — Solid osseous union between roots of teeth and 
their containing alveolar sockets. The condition must not be con- 

80 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM 



8l 



fused with "False" gemination of teeth, for, in the latter, the pre- 
existing sockets have been completely destroyed by absorption 
processes. 




c N 



Fig. 90. — A cemental nodule. Prepared by grinding. Unstained. Mag- 
nified 15 times. D. Dentine; c. Normal cementum; c.N. Nodule. Cf, Fig. 10. 




Fig. 91. — Mesial aspect of a human second maxillary molar with ankylosis of 
its root to the jaw. Slightly enlarged. {From an original photograph.) 

Etiology. — Inflammation of the periodontal membrane aggravated 
or accelerated, or even perhaps originally produced by certain con- 
stitutional dyscrasia, such as gout, rheumatism or other trophic 
neuroses produces it. The probable course of the pathological 
phenomena is as follows: — The root membrane having been attacked 
6 



82 THE DENTAL TISSUES 

by septic or infective micro-organisms, during the course of the 
inflammation, becomes injected with blood due to hyperaemia and 
rapidly becomes infiltrated with inflammatory products. Sup- 
puration ensues. The whole of the membrane then undergoes con- 
version into a thick mass of granulation tissue. The adjacent bone of 
the jaw soon gets permeated with inflammatory products, and under- 
goes a kind of rarefying osteitis, or ulceration. Thus a small-cell 
exudation invades the Haversian canals of the alveolus, and together 
with osteoclasts which may be increased in number, destroys portions 
of the bone, and soon is changed into granulation tissue, which joins 
with the granulation tissue of the root membrane. 

On the cementum side these pathological phenomena do not 
make such marked progress. But it is conceivable that the small- 
cell exudation excavates the periphery of the cementum, producing 
a roughening of the exposed surface, and that the granulation 
tissue of the membrane rapidly passes into and fills the irregular 
spaces so produced. 

The layers of granulation tissue having presently united, a fibrous 
stage is in time reached, and then follows ossification of the entire 
parts. 

Macroscopical Appearances. — Roots of teeth so affected present 
a bony, rough, dull growth on their extremities; they may be bathed 
in purulent effusion (Fig. 91). 

Six cases of synostosis of teeth in man have been placed on record: 
one occurring in the practice of W. A. Whatford, a second by Storer 
Bennett, a third by M. Choquet, a fourth by G. W. Watson, a fifth 
and a sixth by the author. As possessing many points of interest, 
the latter three may be now described. 

MR. WATSON'S CASE 

The size of the mass of bone attached to the tooth was remarkable, 
and some idea of its bulk may be obtained from the following par- 
ticulars: — Its greatest diameter extended in length 17 mm.; the 
greatest depth from apex of the posterior root equalled about 4 mm. 
The inter-radicular regions measuring from the distal ending of the 
dentinal tubes was about 5 mm. See Figs. 92 and 93. 

HISTOLOGY 

The specimens were made from a carious mandibular molar. 
The pulp canals showed no signs of change. 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM 



83 



The cementum at the neck of the tooth was normal, that is to say, 
structureless, no lacunae being present. The lamellae and incremen- 
tal lines were, however, highly pronounced. 

The root membrane was normal just below the cervical margin; 
at some considerable distance above the apex of the anterior root 
it is deflected for a short length over the bony alveolus. 

The granular layer of Tomes is strikingly broad, and its constit- 
uents clearly defined. 




Fig. 92. — Ankylosis of the roots of a human mandibular molar. Prepared 
by grinding. Unstained. Magnified 12 times, r. Apices of the roots; o. 
Osseous tissue; a. Abscess cavity. (From a specimen in the collection of G. W. 
Watson.) 

The cementum towards the apical space becomes trebled or 
quadrupled in width, with marked penetrating fibres, but the inner- 
most zones are devoid of lacunae and canaliculi. The middle and 
outer zones are characterised by the presence, arranged in parallel 
stripes, of incremental lines with dense striae of lacunae and canal- 
iculi. This part of the tissue consists of a dozen or more rows of 
lacunae displayed side by side in due order and regularity. The band 
of tissue sweeps round the apical space, and diminishes in thickness 
as this is reached. 



8 4 



THE DENTAL TISSUES 



The apex of the pulp canal is a little enlarged to give off a devious 
ill-formed passage into a large, almost globular cavity, which from 
certain signs of absorption, probably, in the recent state, contained 
pus. 

Round the internal surface of this root the cementum is enor- 
mously broad, is exceedingly granular, and possesses in its central 




Fig. 93. — Similar to the preceding. Magnified 50 times, d. Dentine; 
h.c. Hyperplasic cementum, occupying what had previously been the periodontal 
membrane; o. Osseous tissue. 

axis many irregular lacunae. The neighbouring surface of the pos- 
terior root is noted for its thickened cementum, myriads of lacunae, 
the canaliculi of which run towards the middle line. The apex and 
distal portions of the second root present granular cemental matrix, 
marked granular layer, and abundant lacunae. 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM 85 




Fig. 94. — Vertical section of radicular portion of a human premolar anky- 
losed to the jaw. Prepared by decalcification. Stained with hsmatoxylene. 
Magnified 10 times. R. Root of the tooth; a. Bone of jaw. 




Fig. 95. — Vertical section of a human tooth ankylosed to the jaw. R. Root; 
b. Bone of jaw. The absolute continuity of the two hard tissues is strikingly 
shown. (From the collection of the late Storer Bennett.) 



86 THE DENTAL TISSUES 

The most external tissue is bone of the alveolus structurally 
altered. There is little attempt at the regular formation of Haver- 
sian systems. The thickest masses contain many elongated spaces 
filled with soft material, and lacunae of every conceivable form and 
size — many of which are abrachiate — abound, some massed together 
and coalesced, others quite discrete. The matrix is rough and 
granular. No well-marked osseous lamellae are visible. The thinner 
region consists of matrix and lacunae. 

At that portion of the mass furthermost from the roots the tissue 
begins to assume the characteristic appearances of cancellous bone. 
The sections are remarkable from the absence of the festooned con- 
tours of the foveolae of Howship. Figs. 91 and 94 are teeth from the 
mouth of a man aged 41, who was suffering 
from suppuration of the socket of a tooth 
which had been recently removed. The 
second right maxillary premolar and the second 
and third molars presented complete synostosis 
of the roots. Fig. 91, from a photograph by 
the author, shows the general macroscopical 
appearances of the second molar, which was 
otherwise normal; and the photomicrograph 
of low power magnification is that of a de- FlG - 96.— Maxillary 

. .j. , , . ■ £ ., . , „. first premolar anky- 

calcmed section 01 the second premolar, rig. i OS ed to alveolar bone. 
96 is noteworthy on account of the large 
amount and size of the bone ankylosed to the root of the premolar. 
Fig. 95 is a photomicrograph of one of Storer Bennett's speci- 
mens. 

(hi) Hyperplasia 1 

Definition. — A pathological overgrowth of cementum due to 
increase in number (not size) of its structural elements. The con- 
dition has been called "hypertrophy" 2 of the cementum. This is 
incorrect, as it is an inflammatory thickening of the tissue. Syno- 
nyms: — Exostosis, cementosis. A nalogne: — Osteoplastic periostitis. 

1 See "A Handbook of Pathological Anatomy and Histology," by Professors 
Delafield and Prudden, p. 93, 1902. 

2 By a simple "hypertrophy," modern pathologists understand simple in- 
crease in size of the elementary structures of a part, leading to structural changes 
the result of increased nutrition, being dependent on excessive functional activity 
of the constituents of that part. Thus, the following examples may be cited: 
hypertrophied bone; enlarged and dilated heart ("compensatory hypertrophy"), 
congenital macroglossia, enlarged tonsils, etc. 




PATHOLOGICAL CONDITIONS OF THE CEMENTUM 



87 



Etiology. — Functional activity of the cells of the periodontal 
membrane under the influence of the inflammation of chronic 
periostitis induces hyperplasia. The membrane becomes hyperae- 
mic and swollen, and a small-celled infiltration occurs. On the 
inflammatory products becoming organised into fibrous tissue, 
ossification of the inner surface may supervene; but the whole 
thickness of the membrane does not calcify. 

Secondary Changes. — None. 

Macroscopical Appearances. — The affection may be so slight as 
to give rise to no appreciable amount of tumefaction. Ordinarily, 






ii^v 



Fig. 97. — Hyperplasia of the cementum. Prepared by grinding. Unstained. 
Magnified 51 times. (Photomicrograph by Douglas Gabell.) 



however, smooth rounded nodules may be seen after removal of 
teeth, or there may be a rough, cancellous, bulbous growth. The 
whole or part of the root may be diseased; a band or mass of new 
tissue may not only produce apparent or real elongation of the roots, 
but actually, in some circumstances, join them or, occasionally, 
even teeth themselves together. This condition is known as 
"false gemination" (see previous chapter). In these extreme 
cases the intervening alveolar septa have been absorbed by the 
small cells (leucocytes) of the inflamed periodontal membrane. 



88 



THE DENTAL TISSUES 




Fig. 98. — Hyperplasia of the cementum. Magnified 150 times, o. Oldest, or 
the earliest deposited layer; Y. Youngest layer. 




Fig. 99. — Lacunae and canaliculi in hyperplasic cementum. Prepared, by 
grinding. Unstained. Magnified 170 times. (Photomicrograph by Douglas 
Gabell.) 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM 89 

To the naked eye the root membrane appears considerably 
thickened and reddened. 
Secondary Changes. — None. 

HISTOLOGY 

The microscopical structures vary in different degrees. Hyper- 
plasia may be limited to the apex of a root, a minute portion near the 
enamel, or midway down the side of the root. 

The chief features of the new growth, in addition to the amor- 
phous or granular matrix, lamellae, and perforating and penetrating 
fibres, are lacunae and canaliculi. It has generally been understood 
these latter bodies exist in normal cementum; but, as has already 
been pointed out in Chapter V., Vol. I., this is most probably an 
erroneous idea. It is appropriate and opportune, therefore, to 
describe cemental lacunas in this place. 

The lacunae somewhat resemble those of bone (q.v.) : but in their 
form, number, size, arrangement and extraordinary length and 
number of their processes, they present several points of difference. 

A cemental lacuna is an irregular space. In dried sections it is 
filled with debris or air, in the fresh state, with some amount of 
living material. It may be rounded, ovate, plumiliform, arbores- 
cent or rimous in shape. The first two conditions most generally 
obtain. The lacunae of bone are much more regular. 

In number, these bodies vary in different parts. Thus at the 
cervical margin they are generally absent. Few in number, and 
isolated in position, they are found midway between the crown and 
the root; while in the apical region they are most abundant. In man, 
the thinnest cementum is almost devoid of them; the thickest is 
always accompanied by them. 

Lacunae differ in size. According to Kolliker, they may range in 
diameter from io/j. to 40^ or 60^. These are average measurements. 
They are larger than those of bone. Those having the greatest 
size are to be found in the inter-radicular regions of molar teeth, and 
also wherever the cementum is thickest (see Figs. 102 and 109). 
There is no definite arrangement of their position as in compact 
bone; they are placed in a haphazard fashion throughout the matrix, 
though sometimes they lie in series, apparently being governed in 
their distribution by the lamellae. Their processes are numerous 
ramified channels, commonly known as canaliculi, which stretch out 
for some considerable distance (sometimes as far as 6ju or 8/x) from 



9 o 



THE DENTAL TISSUES 



the lacuna, to which they very often give a jagged plumiliform ap- 
pearance (see Fig. 101). Branched and irregular in outline, as a 
rule, these offshoots taper towards their free ends where they com- 
monly measure iju. Some end in a cul-de-sac; others anastomose 
with neighbours; others again form the minute extremities of the 




Fig. ioo. — Hyperplasia of the cementum. Prepared by grinding. Stained 
by impregnation with coloured collodion. Magnified 200 times. Shows the 
diversified character of the lacuna;. 



dentinal tubes or their branches, while another set may meet with 
certain processes from the spaces of the granular layer of Tomes. 
In slight cases of hyperplasia it seems to be a normal condition for 
the canaliculi to be given off from all sides of the lacuna; still there 
is often a general disposition on their part to most chiefly extend 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM QI 



•' 




Fig. ioi. — Plumiliform lacunae in hyperplasic cementum. Prepared as in the 
preceding figure. Magnified 250 times. 




Fig. 102. — Rimous and arborescent lacuna? in hyperplasic cementum. 
Prepared as in the preceding figure. Magnified 250 times. 



02 



THE DENTAL TISSUES 



outwards towards the periodontal membrane. In rimous lacunae 
they issue at right angles to the sides as well as the ends; and, in ad- 
dition, in the innermost zone — viz., that first laid down by osteo- 
blasts, the outlines of the lacunae when present are very irregular, 
their canaliculi are short and may blend intimately with many 
elongated canals. In multi-rooted teeth, where cementum is 




Fig. 103. — Cemental lacunae and canaliculi. Magnified 1,000 times. 
(Photomicrograph by Norman Broomell.) 



slightly thicker than elsewhere, the ground substance is particu- 
larly granular; if lacunae are present, they are fairly evenly distrib- 
uted throughout, and many rimous or aborescent spaces are 
found (see Fig. 109). 

According to Tomes (op. cit. p. 117), some lacunae have short cana- 
liculi, and are encapsuled. "Sometimes a line is seen to be surround- 
ing a single lacuna, sometimes several are enclosed within it." 
Capsules are not very common; but, if present, they appear clearly 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM 



93 



defined, are yellowish in colour, have slightly curved borders, and 
may surround an individual or group of lacunae either partially or 
entirely. 

What constitutes the actual contents of these spaces in the fresh 
state has been up to the present time only imperfectly known. Most 
probably, arguing from the sensitiveness of this tissue when exposed, 
each is filled with protoplasm. Heitzmann and Bodecker both claim 
to have proved this as a physiological and histological fact. 

And it is a common experience to find, in sections of hyperplasic 
cementum, when properly prepared, lacunae containing a nucleated 




Fig. 104. — Cemental lacunas in the first-deposited layers of cementum. Magni- 
fied 80 times. (Photomicrograph by Norman Broomell.) 

cell, analogous most probably to the bone corpuscles of ordinary 
osseous tissue. 

In addition, the incremental lines of Salter, generally speaking, 
are strikingly exhibited in ground as well as in decalcified sections. 
They are not, however, always constant, as in Fig. 105. 

If the deposition of the tissue has been conducted on uniform lines, 
the laminae are very regular, the lacunae, though numerous, bear also 
some definite relationship to each other, and are systematically 
arranged with regard to the laminae (see Fig. 107). But when the 



94 



THE DENTAL TISSUES 




Fig. 105. — Hyperplasia of the cementum. Prepared by grinding. 
There are no incremental lines. Magnified 40 times. 



Unstained 




HC 



Fig. 106. — Hyperplasia of the cementum. Transverse section through apical 
region of tooth. Magnified 40 times, d. Dentine; R.c. Root canal somewhat 
enlarged and containing a deposit of ossific or calcific material; H.C. Hyperplasic 
cementum. {From a specimen in the collection of Douglas Caush.) 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM 



95 



HC 




Fig. 107. — Hyperplasia of the cementum. Magnified 40 times. D. Dentine; 
h.c. Cementum in which the lamina? are regularly arranged; v.c. Vascular canal. 
(From the collection of Douglas Caush.) 




HC 



Fig. 108. — External absorption of dentine and deposition of hyperplasic 
cementum. Magnified 45 times, d. Dentine; a. Area of absorption; h.c. 
Cementum. {From the collection of Douglas Caush.) 



9 6 



THE DENTAL TISSUES 




Fig. 109. — Rimous and very large lacuna in hyperplasic cementum. Magnified 
45 times. (From the collection of Douglas Caush.) 




Fig. iio. — Internal absorption ofjjdentine, enlargement of root canal, and 
deposition of osseous or calcific material. Magnified 40 times. D. Dentine; 
r.c. Root canal; o. New tissue deposited in the root canal; H.c. Hyperplasic 
cementum. {From the collection of Douglas Caush.) 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM 



97 




Fig. in. — To show the nature of the new tissue deposited in a root canal 
^ Magnified 250 times. {From the collection of Douglas Caush.) 




Fig. 112. — External absorption of dentine, and deposition of hyperplasic 
■cementum in the absorption areas. Magnified 200 times. (From the collection 
of Douglas Caush.) 



98 



THE DENTAL TISSUES 




Fig. 113. — Similar to the preceding. From the same source. Magnified 200 

times. 




Fig. 114. — Cementum and dentine of a senile tooth. Prepared by grinding. 
Unstained. Magnified 230 times. C Granular, but not lacunated cementum; 
D. Dentine. 



PATHOLOGICAL CONDITIONS OF THE CEMENTUM 



99 



mass is tabulated and has a rugged surface, then the lacunae are 
coarse, large, and provided with long branched deviating processes. 
In the former degree the line of junction with the dentine is sharp 
and clear; in the latter it is often impossible to say exactly where one 
tissue ends and the other begins. 



PM 




Fig. 115. — Senile cementum and alveolar bone. Magnified 45 times. D. 
Dentine; c. Hyperplasic cementum; p.m. Periodontal membrane; b. Osteo- 
porotic alveolar bone. 

Newly formed vascular channels often make their appearance 
in the cementum (Fig. 107) and the phenomena of absorption and 
re-deposition (Figs. 112 and 113) take place side by side in the same 
specimen. The condition is commonly associated with enlargement 
of the pulp canal, and sometimes depositions of new osseous material 
(see Figs. 106 and no). 



IOO 



THE DENTAL TISSUES 



(iv) Senile Cementum 

Of cementum found in aged teeth little need be said. As a rule, 
it is hyperplasic, because few teeth which have been removed from 
the mouth, either from mobility or to relieve pain, have escaped the 
ravages of disease, and their cementum is therefore thickened and 



PM 




Fig. 116. — Senile cementum. Magnified 200 times, d. Dentine; p.m. Homo- 
geneous layer; c. Cementum. 

lacunated. But healthy teeth, which have never been the subject 
of an attack, show that this tissue is somewhat thicker than in 
young adults, but is structureless and similar in every way to normal 
cementum (see Fig. 114. Cf. Fig. 97). j 



CHAPTER IV 

DENTAL CARIES 

Microscopical Elements in: — (i) Nasmyth's membrane; (ii) "White 
spots;" (iii) Zones of partial and complete decalcification; (iv) 
"Secondary enamel decay;" (v) Zone of translucency; (vi) "Lique- 
faction foci;" (vii) "Pipe-stem" appearance; (viii) Opaque zones of 
Miller; (ix) Cementum; (x) "Arrested" caries. 

Definition. — "An acid fermentation during which the inorganic 
portions of teeth are first dissolved, and then the organic portions 
disintegrated by the action of micro-organisms." More shortly: — 
Decalcification of the teeth followed by their dissolution. 

Etiology. 1 — The environment of the teeth. The peptonising 
influences of micro-organisms on the surface, proceeding inwards. 
Strictly it is not a disease, as it cannot be induced at will, in man 
or the lower animals. 

Dental caries has never been noted in the teeth found in ovarian 
teratomatous cysts. 

Macroscopical Appearances. — These are too well known to require 
any special description; suffice to say that enamel loses its polish; 
white, opaque "spots" appear; pigmentation ensues; and in the 
hard parts, cavities are produced. According to certain accompany- 
ing phenomena it has been termed caries acuta, when rapid in 
progress; caries chronica, when slow; caries sicca, when dry; and 
caries humida, when saturated with fluids. French writers speak 
of caries of the " ist degree," " 2nd degree," and so on, thus hinting 
at the extent which has taken place. 

1 The causes of Dental caries, it may be stated in general terms, are not alto- 
gether known. Some authors have divided the causes into (A) Predisposing, (B) 
Exciting. Of these, grouped under the heading of General predisposing causes, 
one finds, (a) Heredity, (b) Improper dietary, (c) Civilization; and under the 
heading of Local predisposing causes, (a) Malposition in the dental arches, (b) 
Structural defects of the surface, and (c) Vitiated oral secretions, produced by 
(i) systemic diseases, e.g., gout, typhoid fever, etc.; (ii) occupation, as in millers, 
or finally, (iii) pregnancy. The Exciting cause is: Bacterial fermentation of 
carbo-hydrates. It is difficult to name the true cause or causes. Probably 
a hitherto undiscovered special caries-producing micro-organism is the chief 
agent. 

101 



102 



THE DENTAL TISSUES 



Secondary Changes. — The condition may become arrested; but 
usually it extends, unless interrupted, until the crowns of teeth are 
destroyed more or less in their entirety. 

Phenomena. — The probable sequence of events in progressive 
caries of the teeth is as follows: — 

i. — Attack on Nasmyth's membrane, 
2. — Formation of "white spots" in enamel, 
3. — Channeling and penetration of enamel by micro- 
organisms, 




Fig. 117. — An early stage of caries of the enamel. Prepared by grinding. 
Unstained. Magnified 45 times. E. Enamel; d. Dentine; w. "White spot;" 
p. Area of pigmentation; f.s. Free approximal surface of the tooth. 

4. — Decalcification of dentine, 

5. — Tubular infection by micro-organisms, with formation 

of "liquefaction foci," 
6. — Fusion of the latter and production of cavities, and 
7. — Dissolution of the hard parts. 
These must now be severally described. 

HISTOLOGY 

(i) Nasmyth's membrane 

Of the histo-pathology of this tissue little is known. Its extreme 
tenuity and its anatomical characteristics, and the difficulty of 



DENTAL CARIES 



103 



making sufficiently satisfactory microscopical preparations have 
given but few opportunities for pathologists to work out its morbid 
anatomy. 

It would appear that the tissue is often more or less deeply pig- 
mented, probably partly through the agency of certain chromogenic 
bacteria, partly through the use of tobacco, or the salts of iron, 
copper and mercury, and partly through post mortem changes common 
to all organic matter; and finally wholly or partially removed by the 
action of micro-organisms and mechanical agencies from the surface 




N M 



ws 



Fig. 118. — Early stage of carie; of enamel. Magnified 90 times, n.m. 
Nasmyth's membrane increased in thickness (? carious); w.s. " White spot ; " 
p. Pigmentation of enamel; e. Non-carious enamel. 



of the enamel. It is believed that the natural acids of fermentation 
have little or no effect upon it, since the translucent pellicle is 
peculiarly resistant to strong acid reagents like hydrochloric, acetic, 
etc. It is, however, evident that the enzymes of bacteria are able 
to disintegrate this film with, probably, the production of a small 
amount of amino-acetic acid. In preparations stained by Gram's 
method, it is possible to see masses of micrococci congregated on 
its surface. 



io4 



THE DENTAL TISSUES 




Fig. 119. — A portion of a " White spot." Magnified 2,000 times. 

graph by Leon Williams.) 



(Pkotomicro- 




F.G. 120. — Section through human enamel, showing the first stages of caries. 
Magnified 2,000 times. {Photomicrograph by Leon Williams.) 



DENTAL CARIES 



I05 



Otto Walkhoff in a recent work' describes and figures, in Plate XL, 
a deposit of green pigment which has taken place, in parallel rows, 
between the "convexities of the enamel." This, no doubt, refers 




Fig. 121. — An early stage of caries of the enamel round the fissure on the occlusal 
surface of a human premolar. Prepared by grinding. Unstained. Magnified 
45 times, p. Carious patch at free end of a deep sulcus; i.e. Developmentally 
defective enamel rods; r. Brown stria? of Retzius; A. Amelo-dentinal junction; 
D. Dentine. 



to the thickest portions of the membrane in the pits and crevices of 
the enamel. 

It may, however, be stated that the precise role played by Nas- 
myth's membrane with regard to dental caries is not at present 

1 "Mikrophotographischer Atlas der Pathologischer Histologic Menschlicher 
Zahne." 



io6 



THE DENTAL TISSUES 



understood. It would seem, however, in the opinion of the author 
to constitute, under favourable conditions, the first line of defence 
against dental caries. Pickerill, and Tomes and Nowell ("A System 
of Dental Surgery," 1906) present the hypothesis that it may act as 




Fig. 122. — Similar to the preceding, but caries more advanced. Prepared 
similarly, with same magnification. Lettering as in preceding figure, b.b. 
Breach of surface. 

a dialysing membrane to certain substances, which may disintegrate 
the surface of the enamel and lead to carious changes in that tissue. 



(ii) "White Spots" 

Quite dark by transmitted light, and often surrounded by a 
pale zone, Fig. 117, these have probably the same histological 



DENTAL CARIES 



107 



features as that surrounding the pigmentation areas in caries. 
The enamel rods in the "white spots" are exceedingly granular, 
and deeply pigmented, their enamel globules, according to Leon 
Williams, having become but imperfectly fused owing to insuf- 
ficiency of cement-substance (Figs. 119 and 120). Very light and 
deeply pigmented patches of enamel alternate irregularly in the 
immediate vicinity of the "white spots." 











m m,\ 




HL B A] 


^kPT& ■ 


HtfSfSfSL^I 




^ ^JmWk \ ■ *W. L 




Wr JR&tn *~W 




JmT ^F . &. M f fl^jfllMB 


PW- 


Mm^k^Kfr 




m& jffliW 










* 


Jtmttk;<.>r- • *' #- 


"- ' ■ 


s HECh^c*. <*^v )'ffil* 




, ^ Htr "s&^wt^Mi ; '.>')'»3 ■■) '/■ 




■' <*»iteFV 


•• 


*» .■' jt ? |KpP7 


r f 


»4. .'' JPr^rir • 


f 


*' *- '' '■'■', ' ' 


j 







M 



Fig. 123. — Caries of enamel. Magnified 90 times. M. Micro-organisms; 
p. Pigmentation of enamel; d. Decalcified enamel; c. Decalcifying enamel. 



(iii) Channeling by Micro-organisms 

The appearances produced by the earliest action of the acids 
generated by the bacteria upon enamel vary. This is due to dif- 
ferences in the structure of the tissue as well as to the variations in 
the products or peptonising effects of the micro-organisms themselves. 
(Leon Williams.) (Figs. 127 and 128.) 

It is still an undecided question whether the "gelatinous plaques" 
of Black 1 and Leon Williams do really exist. They are believed 
to be formed by masses of bacteria which, collecting in suitable 

1 Black, G. V.: "Operative Dentistry," Vol. I, 1908. 



io8 



THE DENTAL TISSUES 



situations, are able by a precipitation of mucilaginous compounds 
to focus in a more or less widespread but yet well-defined fashion 
the operations of the destructive agencies. Kirk 1 has recently 
apparently shown that it is possible to manufacture "bacterial 
plaques" to any size or extent (Figs. 126 and 127). The author, 
however, believes that these "gelatinous plaques" are in reality 
nothing more nor less than portions of Nasmyth's membrane which 
have been retained in situ. For the free surface of such a membrane 




Fig. 124. — Section of normal human enamel. Magnified 350 times. It shows 
a thick, felt-like mass of micro-organisms slightly raised from the surface of the 
tissue (Nasmyth's membrane) produced by pressure of the cover-glass in mount- 
ing. (Photomicrograph by Leon Williams.) 

could afford attachment for material which might become a suitable 
nidus for the development of oral bacteria. 

The acid dissolves out channels, or "wells," whose walls may be 
parallel or V-shaped (Fig. 126). These are most commonly seen 
on the approximal surface of teeth of man; their occurrence 
in the buccal or lingual aspects being less frequent. They penetrate 



1 Kirk: "A Consideration of the Question of Susceptibility and Immunity to 
Dental Caries," Dental Cosmos, 1910. 



DENTAL CARIES 



I OQ 



the intercolumnar substance between the rods, not the rods them- 
selves (Figs. 125 and 126). They are often larger than the di- 
ameter of a rod, and are in no sense of the word developmental 
defects, but merely produced by the acids formed by the enzymes of 
the micro-organisms of caries. 




Fig. 125. — A section of human enamel showing micro-organisms attached to 
the approximal surface of a molar tooth. Magnified 200 times, a.b. The 
commencement of the process of caries by solution of the cement-substance. 
(Photomicrograph by Leon Williams.) 



The acid passes inwards for some distance by means of these 
channels without the production of discolouration. 

Dark bands in enamel, internal to the line of acid penetration, 
probably represent a partial arrest in the action of the micro- 
organisms, which has been presumably brought about by some 
altered conditions of the environment of the tooth (Fig. 132). 

In acute caries the acid penetrates quickly and deeply along 



no 



THE DENTAL TISSUES 



the lines of least resistance, i.e., the cement substance, the rods 
themselves undergoing isolation, and becoming disintegrated before 
their morphological characters are lost. In chronic cases, however, 
the whole substance of the rods is permeated by acid, the result being 
the appearance of a "sponge-like structure," giving the effect of 




Fig. 126. — Section of human enamel. Magnified 350 times. It shows a 
deeply stained mass of micro-organisms attached to the surface, and, at w, 
further action of the acid in dissolving the cement-substance and forming V- 
shaped spaces between the enamel rods. (Photomicrograph by Leon Williams.) 

discolouration in sections when viewed by transmitted light, and 
chalky white by reflected light (Leon Williams). 

Thus, acute white caries is unaccompanied by discolouration, and 
is due to solution of the intercolumnar substance; chronic caries 
to impregnation with the products of bacteria and associated with 
marked discoloration. These changes are macroscopically invisible, 
and occur before a breach of surface results. 



DENTAL CARIES 



III 



With regard to congenital defects in enamel, it is almost con- 
clusively proved that they are not favourite sites for the development 
of caries; but that the micro-organisms most frequently act on enamel 
which is not over the cusps of teeth, where it is usually most defec- 
tive. Caries often begins, as is well known, from a clinical stand- 




Fig. 127. — A section of human enamel from the approximal surface of an 
incisor. Magnified 175 times. Showing enamel nearly penetrated by dental 
caries, a. The carious process apparently arrested by a line of stratification. 
Micro-organisms (attached to Nasmyth's membrane) slightly raised from floor 
of cavity by shrinkage caused by mounting in balsam. (Photomicrograph by 
Leon Williams.) 



point, on approximal surfaces of the teeth, and here the enamel is, 
probably, more perfectly formed than elsewhere. But, while bac- 
teria act independently, there is no doubt that they avail themselves 
of the presence of pits and fissures, being governed in their disposi- 
tion on the surface of enamel by the completeness or incompleteness 
of the translucent pellicle of Nasmyth's membrane. The explana- 



112 



THE DENTAL TISSUES 



tion would appear to be, that having once penetrated through ar 
abraded edge of the membrane they can pass beneath it to 
some considerable distance. If this is true, the phenomena of 
caries beginning in pits and fissures would be accounted for. 

At a somewhat later stage, carious enamel, under the microscope, 
shows that the individual rods are pronounced, their intercolumnar 




Fig. 128. — A section of carious enamel. Magnified 550 times. The bacteria 
have been removed to shew the action of the acid on the enamel rods. (Photo- 
micrograph by Leon Williams.) 



substance partially loosened (Figs. 128 and 130), and clearly ex- 
hibiting spaces between the enamel columns. The strias are very 
marked. This is on the surface. Lower down, the structure is 
indistinguishable, the rods are confluent, and have lost their outline; 
they appear exceedingly granular. Still deeper, they have dis- 
appeared, their place being occupied by masses of micro-organisms, 
which are clearly revealed when the section has been stained with 



DENTAL CARIES 



"3 



i) 




Fig. 129. — A section of carious enamel, showing appearances of the tissue in 
a case of chronic caries. Magnified 2,000 times. The cement-substance has 
been dissolved away, thus exposing to view the original organic matrix. The 
globular bodies or sections of the rods are shown at a, b, c, d, and are seen 
to be identical in general shape and character with those originally formed in 
the ameloblasts and on the surface of forming enamel. (Ph lomicrograph by 
Leon Williams.) 



ii4 



THE DENTAL TISSUES 



gentian-aniline-violet, fuchsine, or other aniline dyes. Bacteria 
may be seen occupying the spaces between the rods if a minute 
fragment of "secondary enamel decay" is examined. 

The loosening of the rods is said to be dependent on the action 
of lactic acid. Tomes believes that the axes of the enamel columns 




Fig. 130. — A cover-glass preparation from scrapings;of white, opaque carious 
enamel. Magnified 450 times. The cement substance between the rods is seen 
to be dissolved away, and the crevices thus formed are filled with round and 
rod forms of micrococci and bacteria. Stained by Gram's method. (Photo- 
micrograph by Leon Williams.) 

are attacked before their peripheries. This, no doubt, is the case 
where the tissue is at all ill-formed. 

Hence there are three zones or areas in enamel which show 
different appearances: — 

(i) The zone of partial decalcification, where the rods are in- 
dividually distinct, the striae marked, and tie cement sub- 
stance partially disintegrated, 



DENTAL CARIES 



115 



(ii) The zone of complete decalcification, in which the rods are 
structureless, but possess a marked degree of granularity; 
And 

(iii) The zone of "secondary enamel decay," in which masses of 
micro-organisms only can be demonstrated (see Fig. 139). 




Fig. 131. — Caries of the enamel, having produced a breath of surface. Pre- 
pared by grinding. Unstained. Magnified 45 times, p. Carious patch in 
enamel; i.e. Imperfect enamel rods; r. Striae of Retzius; d. Dentine. 



(iv) Decalcification of Dentine 

This invariably, in a fairly regular line, precedes the bacterial 
infection of the tubes. The dentine stains easily with histological 
reagents. Unstained it is pigmented, being pale yellow or brown in 
colour. 



n6 



THE DENTAL TISSUES 



A microscopical appearance of great importance in the region of 
advancing decalcification is the presence of the "zone of translucency" 

(Fig- i37) 

The term is applied to an area of increased transparency in that 
part of the dentine which is situated between the advancing caries 




Fig. 132. — A further stage of the preceding figure. Prepared similarly, and the 
same lettering. Magnified 25 times. 



and the healthy tissue. In longitudinal sections it often appears 
conical in shape, the apex being towards the pulp, the circular base 
towards the periphery of the dentine. The shape of the figure is, 
no doubt, governed by the convergence of the dentinal tubules, 
which radiate from the pulp outwards in a centrifugal direction. It 



DENTAL CARIES 



117 



may present the character of hyaline stripes or spots; and apparently 
owes its existence to the close approximation of the index of refrac- 
tion of the dentinal tubules and their contents in this situation, 
to that of the matrix of the surrounding dentine. 

Amongst the various phenomena of dental caries it would be 
difficult to find any of greater interest or upon which opinions still 
differ more than the nature of this "translucent zone." It is not 




Fig. 133. — A further stage of caries of the enamel. Similarly prepared and 
lettered to the preceding. Magnified 45 times. The large cavity is easily 
recognised. 



always found in carious dentine, and sometimes it exists in places 
where there is not a trace of the condition. 

Two main opinions are still held regarding its production. Thus, 
Sir John Tomes and Miller, 1 with Magitot, 2 and others, considered 
it due to vital action on the part of the dentine, which leads to a 
calcification of the dentinal fibril. 



1 "Micro-organisms of the Human Mouth," 1889. 

2 "Traite de la Carie des Dents," 1867. 



n8 



THE DENTAL TISSUES 



And secondly Wedl, 1 Black, 2 Leber and Rottenstein, 3 C. S. Tomes, 
F. J. Bennett, 4 and Abbott, regard it as an area of partial decalcifica- 
tion, with obliteration of the dentinal tubules by swelling of the basis 
substance. Bennett says that enlarged and thickened tubules can 
be demonstrated in parts (loc. cit. p. 162). 



PE 



PE 




PE 



PD 



Fig. 134. — An early stage of decalcification of the dentine. Prepared by 
grinding. Unstained. Magnified 25 times, p.e. Carious enamel; p. d. Pigmen- 
tation area in dentine; d. Normal dentine. 

The Vitalists' arguments cannot be put entirely out of court be- 
cause there is no doubt that dentine is endowed, more or less, with 
a modified form of vitality. The chief points are these: — ■ 

(^4) The zone does not form in "dead" teeth. 

1 "Pathologie der Zahne," 1870. 

4 "American System of Dentistry," 1887. 

3 "Caries der Zahne," 1867. 

4 Trans. Odonlo. Soc. of Great Britain, 1895. 



DENTAL CARIES 



119 



Miller examined both macro- and micro-scopically teeth which 
had been worn on plates, and he never found one specimen which 
gave signs of the zone. A large number were subjected to the naked 
eye test, while about a dozen different "dead" teeth were ground 
down and examined microscopically. 

(B) The zone is seen in cases where enamel has undergone attri- 
tion and where caries is absent. 

(C) Narrow bands of translucent dentine sometimes extend even 
to the pulp chamber. This is never the case with decalcification, 
which proceeds through the tissues in a fairly regular line. 




Fig. 135. — A further extension of caries, showing penetration to the cortex 
of the dentine of the carious cavity. Prepared by grinding. Unstained. Mag- 
nified 20 times, c. Carious enamel; c.d. Carious dentine. 



(D) The chemical analysis of the dentine in the translucent zone 
does not yield results at all compatible with the decalcification theory. 
Normal and translucent dentine were tested; the former yielded 
72.1 per cent, of lime salts; the latter 71.9 per cent., a difference, 
as Miller pointed out, quite within the limits of the errors of ex- 
periment. Jeserich analysed the translucent and normal dentine of 
twenty teeth, and his experiments showed that the former contained 
69.5 per cent, and the latter 68 per cent, of lime salts. These results 
do not indicate any decalcification. 



120 



THE DENTAL TISSUES 



(E) The zone is difficult to stain with eosin, fuchsine, and other 
aniline dyes; whereas decalcified dentine is easily coloured by 
similar re-agents. 

(F) The zone cannot be produced in vitro. 




Fig. 136. — A further extension of the carious process in dentine. Most of 
the enamel was removed during the act of grinding the section. Unstained. 
Magnified 12 times. E. Enamel; D. Dentine; c. Cavities produced by caries; 
CD. Carious dentine, the tubes of which are infected by micro-organisms; 
D.D. Decalcified dentine; p.z. Pigmentation zone of decalcified dentine. 

In addition, Walkhoff deliberately asserts that there is a diminu- 
tion in size of the calibre of the tubules, as well as in the diameter of 
the fibrils. 

Wellauer says that there is a contraction of the lumen of the 
tubule; and Baume, that this contraction leads, in time, to absolute 
obliteration of the tubules. 



DENTAL CARIES 



121 



On the other hand, the Devitalists hold that: — 

(A) The zone is found in "dead" natural teeth which have been 
subsequently attacked by caries, after they have been mounted on a 
plate and worn in the mouth for some time: 




P.D 




T Z 



D 



Fig. 137. — Translucent zone in dentine, cut obliquely. Prepared by decal- 
cification in hydrochloric acid, stained with Ehrlich's acid' ^haematoxylene. 
Magnified 35 times. E. Enamel; A. Amelo-dentinal junction; D. Non-carious 
dentine; T.z. Translucent zone; p.D. Oblique patch of pigmented decalcified 
dentine. 



(B) It exists in cases of partial arrest of caries in teeth, where it 
might be easily supposed that calcification of the fibrils and tubules 
was actually taking place: J>. Xurr 

(C) The tubules in the zone are rather enlarged and thickened, 
presenting "pipe-stem" appearances. 

Further, Leber and Rottenstein state that it is softer than the 



122 



THE DENTAL TISSUES 



normal surrounding dentine; and Wedl proved the patency of the 
tubules in the zone by immersing in a solution of carmine several 
dried sections of the transparent roots of senile teeth. The stain 
passed up the tubules quite easily. 




Fig. 138. — Extensive caries of the coronal region of a human canine tooth. 
Prepared by grinding. Unstained. Magnified 30 times, e. Enamel; r. 
Brown strias of Retzius; s. Lines of Schreger; d. Dentine; 0. Carious cavities on 
labial aspect of the tooth extending laterally and undermining the enamel; 
C2. The same on the lingual surface; p. Pulp cavity. The enamel has not been 
fractured during the act of grinding the section. 



The arguments and theories on either side are very cogent, 
and one cannot say, in the present state of knowledge, which is 
correct. But it is interesting to know that similar appearances have 
been found in cases of attrition and erosion of the teeth. 



DENTAL CARIES 



123 




CD 



Fig. 139. — Coronal section of a human premolar, with extensive caries of 
enamel and dentine. The section is rather thick in order to retain the enamel 
in situ without fracture. Prepared by grinding. Unstained. Magnified 15 
times. E. Normal enamel; c.E. Carious enamel; r. Brown striae of Retzius; 
d. Normal, but very pigmented dentine; p. Pulp cavity; s.e. "Secondary enamel 
decay;" CD. Carious dentine; d.d. Disintegrating dentine in cavity on the buccal 
aspect of the tooth. 



124 



THE DENTAL TISSUES 



CD 




S ED 



C C 



Fig. 140. — Sagittal section of a human incisor tooth. Similarly prepared 
and magnified as the preceding, c. Carious cavity with deep pigmentation'of 
the dentine, on th; lingual aspect of the tooth; c.c. Carious cavity extending 
towards the mesial and distal sides of the tooth; c.p. Cornu of pulp which has 
undergone calcification; s.e.d "Secondary enamel decay;" c.D. Caries of the 
dentins e<tending in a lat ral direc'ion. 



DENTAL CARIES 



12: 




Fig. 141. — Sagittal section of a human incisor tooth. Prepared by grinding. 
Unstained. Magnified 20 times, e. Normal enamel; ci. Carious cavity on the 
labial surface; C2. The same on the lingual surface; l. Extension of cavity under- 
mining the enamel; d. Carious dentine. 



126 



THE DENTAL TISSUES 




Fig. 142. — Tubular infection of the dentine by micro-organisms. Prepared 
by the decalcification of carious dentine. Stained by Gram's method. Magni- 
fied 250 times. D. Normal dentine; c.T. Micrococci in the tubules 



CF 




C T 



Fig. 143. — Tubular infection of the dentine, with the formation of "lique- 
faction foci." Prepared as in the preceding. Stained with Ehrlich's acid 
haematoxylene. Magnified 50 times, d. Dentine at margin of cavity, softened 
and disintegrated by the action of the micro-organisms; F. "Liquefaction focus" 
running parallel with the tubes; f.t. The same running across the tubes; c.T. 
Carious infection of the tubules; c.f. Coalescence of several small "foci." 



DENTAL CARIES 



127 




Fig. 144. — Similar to the preceding. Prepared and stained similarly, 
ing similar, d.d. Disruption of the dentine. 



Letter- 




Fig. 145. — A "liquefaction focus" from the preceding figure. Magnified 300 
times. D. Deflected tubes, mentioned in the text. See page 135. 



128 



THE DENTAL TISSUES 



Miller observed and described 1 the presence of opaque stripes or 
zones which border on the translucent zone. Under the microscope 
they appear almost black, and the tubules in these areas are found 
full of irregular, angular granules or rod-shaped elements. The 
opaque zones are almost constantly associated with the transparent 
zones,' and usually separate the latter from the normal dentine, or 
fill up the space between the transparent zone and the pulp. 

These differ from the rod-shaped elements or fragments in the 
tubules of carious dentine first noticed by Sir John Tomes. They 



L F 




Fig. 146. — Caries of dentine. Magnified 450 times, m. Micro-organisms in 
dentinal tubes (pure infection); l.f. "Liquefaction focus." 



are often seen, and were believed by their discoverer to be "portions 
of consolidated dentinal fibrils," or "bits of the sheaths of 
Neumann," or "casts of the enlarged tubules." They are sometimes 
seen in artificial caries, and if brought into contact with dilute 
sulphuric acid completely disappear. 

Rows of shining irregular granules are also met with in advance 
of cariesd. It is possible that they have the same origin as the rod- 
shaped elements just alluded to. Tomes, Magitot, and others 
described them as "lime-granules," while other observers believe 
them to have a fatty nature. 

1 " Trans. Odonto. Soc. 0} Great Britain,'" p. 39, 1895. 



DENTAL CARIES 



129 



L F 



LF 




L F 



Fig. 14 . — Similar to preceding. Magnified 450 times M. Micrococci; 

L.F. "Liqueiac. ion foci. " 




Fig. 148. — Micrococci in the dentinal tubes, from a section of dentine in 
which caries was induced experimentally in vitro. Prepared by the Author's 
method for the production of artificial caries. Stained by Gram's method. 
Magnified 750 times. M. Tubule infected by micro-organisms; x. Non-infected 
tubule. 



130 THE DENTAL TISSUES 

(v) Tubular infection by micro-organisms and formation of 
" liquefaction foci ' ' 

Examined under a low power (16 mm. objective), a section of 
carious dentine stained by Gram's method, appears of a pale yellow 
colour, faintly showing the tubules in the unaffected parts, and 
lines of stain extending inwards from the margins of the cavity. 
These run in a parallel direction (see Fig. 148), some passing through 
the whole of the tissue, others traversing part of the distance. In 
addition, near the margin of the cavity, irregular spaces can be 




Fig. 149. — Micrococci in the dentinal tubules. Stained by Gram's method. 

Magnified 550 times. 

found, in a line with the stained streaks (Figs. 143 and 144). These 
spaces vary considerably in shape and size. They are large and 
irregular near the carious cavity, smaller near the pulp. Here they 
are less irregular, are oval in shape, and are in direct continuity 
with the dentinal tubules ("liquefaction foci.") 

If now, a higher power be used for examining the section (0.9 mm. 
homogeneous immersion objective), the stained streaks are seen to 
be composed of crowds of micrococci and bacilli (see Figs. 148 and 
149), and the spaces, in parts, empty, with disorganised tissue at 
their edges, and in parts filled with micro-organisms. Of all the 



DENTAL CARIES 



131 




Fig. 150. — Similar to the preceding. 




Fig. 151. — Bacilli and micrococci in the dentinal tubules, c. Micrococci; 
B. Bacilli. (Photomicrogr a ph by Howard Mummery.) 



132 



THE DENTAL TISSUES 



varieties, the spherical forms largely predominate, either singly or 
in pairs, or chains, or clusters. Occasionally the tubes may contain 
rods, or even threads; a mixed infection also is far from uncommon. 
(Fig. i S i.) 

Leptolkrix buctalis, and other thread forms, with torulae, and 
some micrococci fringe the edges of the carious cavity, as in Fig. 152. 

Normal interglobular spaces seem to afford a convenient locality 
for the housing of the germs. They (the germs) often spread in a 
lateral direction via the interglobular spaces; but once having 




Fig. 152. — Thread forms of bacteria fringing a carious cavity in the dentine. 
Prepared by decalcification. Stained by Gram's method. Magnified 280 
times, d. Carious dentine; m. Mass of micro-organisms; t. A tuft of thread- 
shaped micro-organisms. 

passed them they extend directly inwards towards the pulp, by 
means of the tubules. 

All portions of dentine are not affected; the boundary between 
the infected and non-infected parts being very regular. This 
zone is called " the non-infected zone," and shows that decalcification 
of dentine precedes its infection by bacteria. 

After the micro-organisms have once entered the tubules, they 
easily pass along their lumina. The canals then become choked 
with micrococci, gradually enlarge, and give way in various places. 
These masses are called "liquefaction foci," and they correspond 



DENTAL CARIES 



1.33 




Fig. 153. — Similar to the preceding. Rod-shaped micro-organisms entering the 

dentinal tubes. 







Fig. 154. — The "pipe-stem" appearance of carious dentine. Prepared as 
in Fig. 152. Stained by Gram's method. Magnified 280 times. 1. Infected 
tubules; N. Non-infected tube; M. Micro-organisms in the matrix of the dentine. 



134 



THE DENTAL TISSUES 



to the "varicosities and globular swellings" mentioned by Sir 
John Tomes in his earlier writings. 

Heider and Wedl ("Atlas zur Pathologie der Zahne," Leipzig, 
1869) describe and figure enlargement of the dentinal tubes which 
possibly are undergoing changes towards those of "liquefaction 
foci." Isolated from the dentine on the border of the softened 
carious portion by means of dilute hot hydrochloric acid, they were 
characterised by a considerable amount of tumefaction, by the 




CD 



Fig. 155. — Carious dentine; tubes cut obliquely. Magnified 450 times. D. 
Non-infected dentine; CD. Carious dentine. 

issuing from them of short lateral branches, and by being covered 
in places with tiny clusters of globules. 

If the enlargement of the tubules continues, contiguous "lique- 
faction foci" become fused, and a space or cavity of an irregular 
shape is produced. The dentine ultimately becomes more and more 
cavernous, and so is gradually broken up, and its debris finally 
washed away by the oral fluids. 

If transverse sections be made near the healthy dentine, the 
"pipe-stem" appearance first described by Tomes is visible (Fig. 
154). This is the result of the enlargement and thickening of Neu- 
mann's sheaths. How this enlargement is brought about is by no 



DENTAL CARIES 



135 



means understood. Miller attributes it, to quote his words, to 
" the pressure of the fungal masses in the tubules, by which a com- 
pression of the walls is caused." 

The author believes that the prominence of these tubules is 
occasioned by two factors: — (i) An actual enlargement of their 
diameters; and also (ii) An actual but slight thickening of their 
sheaths. 

The expansion is produced by pressure of the micro-organisms 
in an outward direction on the peptonised or decalcified dentinal 




Fig. 156. — Similar to the preceding. Magnified 600 times. 

matrix (see Fig. 145). Sometimes the tubules, as at (d), are 
deflected in their courses by the lateral enlargement of the "lique- 
faction focus." 

The thickening of the specially resistant walls is actually pro- 
duced by the enzymes of the micro-organisms within, the elastin 
which they contain, being probably converted into immeasurable 
quantities of amino-acetic acid. 



(vi) Fusion of Liquefaction Foci and Production of Cavity 

The pressure of the bacterial masses on the softened intervening 
matrix soon causes the foci to amalgamate. In process of time a 



136 



THE DENTAL TISSUES 




Fig. 157. — Similar to the preceding, but the tubules are cut obliquely 

Magnified 600 times. 




Fig. 158. — Similar to the above, but the tubules are cut slightly obliquely. 

Magnified 280 times. 



DENTAL CARIES 137 

cavity is formed by the coalescence of many foci, its contents being 
of a soft cheesy consistency, and crowded with micro-organisms. 
The walls of the cavity become extended by the rapid multiplication 
and peptonising action of bacteria, and the final stages are reached by 
the undermining and subsequent fracture of the walls (Fig. 162). 
An attempt has been made in the accompanying photomicrographs 
to illustrate these various stages. 




Fig. 159. — Round and rod-shaped bacteria in the matrix of carious dentine. 
Stained by Gram's method. Magnified 600 times. 



(vii) Caries of the Cementum 

Caries of the cementum is less common than that of enamel or 
dentine. It can be well observed on the exposed surface of the 
palatine roots of maxillary molars when, through septic infection, 
these have been denuded of their alveolar sockets and periodontal 
membranes. 

The microscopical appearances are interesting, because they show 
that the micro-organisms gain admission to the short canals occupied 
by the penetrating fibres of Sharpey, and cause their contents to 
swell. It proves that these fibres fill these bony channels somewhat 
similarly to the fibrils in the dentinal tubules. Probably the process 
of caries in cementum is not quite analogous to that in dentine. In 



138 



THE DENTAL TISSUES 



consequence of its close association with the periodontal membrane, 
the condition is usually checked in advancing at the border of the 
tissue. Roots of teeth are often seen in which the dentine has 
nearly all disappeared, merely a thin shell of cementum being re- 
tained in situ. The real reason of this would appear to be accounted 
for by the absence of tubes or lacunae in the homogeneous layer of 
the dentine the non-tubularity thus prohibiting here the admission 
of micro-organisms. 

(viii) "Arrested" Caries 

Little is known of the physical, chemical, and histo-pathological 
changes which bring about this condition. In the enamel, pigmen- 




Fig. 160. — Masses of micro-organisms in the matrix of very carious dentine. 
Staining and magnification as in the preceding figure. 



tation extending inwards to varying depths is noticed; the inter- 
columnar substance is well-defined; the rods themselves present 
a homogeneous appearance. The brown striae of Retzius and 
Schreger's lines may or may not be entirely obliterated (see Fig. 
200). In the dentine, the circumferential tubes are occluded, the 
refractive indices of tubes and matrix thus approximating. In the 
pulp, adventitious dentines of one or more types may generally 
be found. 



DENTAL CARIES 



139 



(ix) The Micro-organisms of Dental Caries 

The micro-organisms normally found in the human oral cavity 
are of all kinds: cocci occur most abundantly, but also bacilli 
thread-forms, sarcinae and spirilla. It is probable that, of the first 
named the Streptococcus viridans, the Staphylococcus pyogenes aureus 
and the Diplococcus pneumonia are the commonest of the patho- 
genic varieties. In addition many aerobic and anaerobic spore- 
forming bacilli are taken in through the media of air, food, and 
water (see Chapter XVI). 




-4,:IA ■■■■;■ 



A D 



Fig. 161. — Enamel in "arrested caries." Magnified 90 times, e. Carious 
enamel; a.d. Amelo-dentinal junction; D. Normal dentine. 

It is difficult to determine with any degree of accuracy the mor- 
phological and biological characteristics of the actual producers of 
dental caries; it is so extremely easy, even with the utmost care, 
to obtain bacteria for experimental purposes that are incapable 
of causing the initial decalcification of the enamel. Nor is it yet 
ascertained whether the bacterial factors which may occasion the 
dissolution of the peripheral hard parts of the teeth are the same as 
those inhabiting the dentinal tubules, or the surfaces of carious 
cavities. The saliva carries with it, and sweeps into such cavities, 
adventitious bacteria. Others from the oral mucous membrane, the 



140 THE DENTAL TISSUES 

gingival troughs, the alveolar "pockets," the tonsils and pharynx, 
add their quota to the varieties of the oral flora and make real 
discrimination between the caries-producing and the non-caries- 
producing organisms very difficult. On microscopical examination 
of a fragment of carious enamel or dentine, multitudes of bacteria are 
observed: but it is almost impossible to affirm with certainty whether 
those present are such-and-such organisms. Identification is 
often impossible. The bacteria of caries as Goadby 1 points out 
appear to be influenced very largely by their environment; and it is 
quite possible that the actual producers of the dissolution of the 
enamel are often overwhelmed by the preponderating growth of 
others, which, as secondary agents of "dental decay," penetrate the 
dentinal tubules and peptonise their walls. 

Several facts, however, would seem to stand out pre-eminently. 
The bacteria in superficial parts are aerobic; those beneath, in the 
vanguard of the advancing host, anaerobic or facultative aerobic; 
many as yet, cannot be cultivated on the ordinary laboratory media; 
the superfically placed bacteria produce proteolytic enzymes, others 
fermentation with acid production; no liquefaction of undecalci- 
fied dentine takes place by means of the proteolytic enzymes; and 
finally it is practically impossible to differentiate between pathogenic 
and non-pathogenic forms. For according to Emery ("Immunity 
and Specific Therapy," 1909), "any bacterium will produce disease 
if it grows in the tissues of the living body, and all bacteria — those 
growing only at very high or very low temperatures or on media 
very poor in nitrogen perhaps excepted — will do so if the necessary 
degree and form of immunity is not present." 

As far as is at present ascertained, it may be briefly stated that 
the micro-organisms found in the superficial parts of carious dentine 
are either liquefiers of that tissue, when it has already been decalcified 
to a certain extent, or are merely enzyme producers. To the former 
group belong, in alphabetical order, the Bacillus furvus, Bacillus 
gingiva pyogenes, Bacillus liquefaciens fluorescens motilis, Bacillus 
mesentericus fuscus, ruber, and vulgatus, Bacillus plexiformis, Bacillus 
subtilis, and Proteus vulgaris; to the latter the Sarcina alba, auran- 
liaca and lutea, Staphylococcus albus and aureus, and Streptococcus 
viridans. Those isolated from the deeper layers of carious dentine 
are the Bacillus necrodentalis, and Staphylococcus albus. A third 
class includes the chromogenic bacteria. Fringing the edges of 
carious surfaces are many thread-like organisms. These often in- 

1 "The Mycology of the Mouth," 1903. 



DENTAL CARIES 



141 



elude Leptothrix innominata, Leptothrix buccalis maxima, Streptothrix 
buccalis, and the curved and spiral forms described as the Spirillum 
sputugenum, and Spirochete dentium. 

EPITOME OF MICROSCOPICAL APPEARANCES OF CARIES 

i. Nasmyth's Membrane shows mere pigmentation. 

2. Enamel. — The rods are separated; their striae pronounced; 




Fig. 162. — Final stages in the destruction of carious dentine. Prepared by 
decalcification. Unstained. Magnified 40 times, d. Carious dentine; p. 
Pulp cavity. 

are granular, and broken down. Bacteria pass between them and 
take their place in "secondary enamel decay." Three zones are 
present, viz., those of partial decalcification, complete decalcifica- 
tion, and "secondary enamel decay." 



142 THE DENTAL TISSUES 

3. Dentine. — Tubules filled with micrococci and bacteria; "lique- 
faction foci" are formed. "Tobacco-pipe appearances" and "Zone 
of translucency" are noticed. The opaque zones of Miller 
frequently exist. In some places rod-shaped fragments fill the 
tubules. Homogeneous layer usually non-infected. 

4. Cementum. — Fibres of Sharpey are attacked by micro-organ- 
isms, the dentinal surface meanwhile unaffected. 



CHAPTER V 

THE DISEASES OF THE DENTAL PULP 

Microscopical Elements in: — (i) Hyperemia; (ii) Acute and Chronic 
Inflammation; (iii) Infective Gangrene of the Pulp; (iv) The 
Pathogeny of Gangrene of the Pulp. 

GENERAL CHARACTERISTICS 

In nearly every case of dental caries there are certain morbid proc- 
esses found in connection with the dental pulp. The majority of 
the pathological conditions met with in this organ are due to causes 
operating from the outside, only a few being determined by and 
dependent on endogenetic disturbances. 

^Etiology. — The causes of diseases of the dental pulp generally 
may be classified as (A) Predisposing, (B) Exciting. 

(A) Predisposing Causes. — (i) General: (a) Physiological, e.g.: 
Heredity, age, sex; (b) Pathological, e.g.: Marasmus, long-con- 
tinued fevers, gout and similar dyscrasia; (2) Local: Anatomical 
peculiarities of the dental tissues. 

(B) Exciting Causes. — (1) General: Effects of disease of (a) Vas- 
cular system, e.g.: Anemia, chlorosis, gout, etc., and (b) Nervous 
system, e.g.: Neurasthenia, etc.; (2) Local: (a) Apparent — Effects 
of dental caries; (b) Non-apparent — Thermal, chemical, and 
electrical stimulations, etc. 

It is extremely probable that morbid affections of Nasmyth's 
membrane or enamel per se (both products, as already described in 
Chapters II and XII, Vol. I, of the stomodaeal ectoderm) exert some 
unknown influence on the subjacent tissues. This, and the two fol- 
lowing Chapters, however, are concerned with the variations that take 
place in the pulp at periods of time antecedent and posterior to the 
carious penetration of its containing cavity: as also the histological 
elements in the pathogenic changes it undergoes through traumatic 
and degenerative lesions. 

It is necessary, at the outset, to again remind the student of the 
fact that the pulp has no pathology peculiar to itself. It shares 
with other organs of a highly vascular nature phenomena of an 

143 



144 THE DENTAL TISSUES 

identical kind, differing mainly in the particulars that it is enclosed 
in a bony casing which prevents much inflammatory exudation, or 
swelling. This confinement in hard unyielding walls probably pre- 
vents, in no slight degree, the tendency for an exposed pulp to cica- 
trize, and induces, in the majority of cases of acute inflammation, the 
death of the pulp in part or in whole. 

Peripheral carious stimulation of the dentine is accompanied by 
destructive as well as constructive metamorphoses; tissue waste and 
tissue repair go on side by side. At first the soft parts alone suffer; 
the dentinal fibrils and their enclosing tubules, in parts of their 
courses, are affected and soon become disorganised, the blood-vessels 
and tissues of the pulp meanwhile undergoing hypertemic and other 
changes. Thus a superficial carious patch beneath the cortex of the 
enamel is associated with marked cellular activity on the part of the 
pulp; while there is a loss of substance externally, there is a gain in- 
ternally. This is exemplified in the formation in certain circum- 
stances of "dentine of repair." In other words, caries, even in its 
early stages, usually leads to a deposit of new adventitious dentine 
on the surface of the pulp. 

But, later on, bacterial agencies multiply and accumulate; 
advancement renders them still more potent; and development 
means destruction. For now not only do the dentinal tubules and 
matrix also become involved in the general dissolution, but any ad- 
ventitious tissues that may have been developed, rapidly break 
down, and soon the work of demolition is complete. A study of 
these phenomena possesses many points of profound interest. 

Hyperemia of the Pulp 

This condition is analogous in all respects with active or arterial 
hyperemia and passive or venous hyperemia occurring in other soft 
tissues of the body. It may be partial or complete — confined to 
one of the cornua or the coronal, cervical, or radicular portions of 
the pulp cavity, or distributed throughout the whole of the soft 
tissue. It is probably dependent, in the first instance, on irritation 
of the dentinal fibrils, produced by various causes, and may pass 
quickly on to acute hyperaemia and inflammation of the pulp. It 
has been called "Irritation of the pulp," an incorrect appellation, for 
irritation is the cause, not the actual disease. The first change from 
normal to an abnormal state of the pulp is not irritation but hyperze- 
mia— if slight it is usually regional, if intense diffuse. 



DISEASES OF THE DENTAL PULP 1 45 

Etiology. — Any factor that determines an increase of the flow of 
blood in the tissue is the cause of hyperaemia. Thus it may be 
ascribed to: — (i) Caries, (ii) Injury to the dentine, which sets up 
dentinal irritation, (iii) Early stages of cold, (iv) Rheumatic affections 
of the jaws, and (v) possibly Hydrargyrism. 

Secondary Changes. — Resolution or inflammation, most com- 
monly the latter. 

GENERAL CONSIDERATIONS 

The nutritional well-being of the pulp depends upon the proper 
regulation of its blood supply, which is governed by the influence 
of the sympathetic nerves of the unstriated muscle fibres in the walls 
of the arteries, the elastic tissue in the tunica media of the vessels 
maintaining simultaneously the necessary " tone. " When the usual 
amount of blood exceeds this physiological limitation, pathological 
hyperaemia is induced and may be (A) Active or arterial, or (B) 
Passive or venous, according to which set of vessels are most chiefly 
affected. 

(A) Arterial hyperaemia may be induced by any condition which 
either (i) paralyzes the vaso-constrictor nerves or (ii) stimulates the 
vaso-dilator nerves, or (iii) weakens the tunica media or (iv) removes 
the extra-vascular pressure. All these factors may act singly or in 
concert with one another. 

If a sufficiently large area of dentine has been exposed during 
the course of dental caries, various forms of irritation may set up a 
localized regional hyperaemia. Such forms of irritation are the 
chemical or bio-chemical products of decomposition of liquid or 
soft food, vitiated oral secretions, thermal changes in the mouth, 
and drugs medicinally or artificially applied for therapeutic purposes. 
Cold paralyzes the vaso-constrictor nerves; heat, the vaso-dilators, 
while the alteration of the protoplasmic contents of the dentinal 
tubes by the products of bacteria and the use of chemical reagents 
probably weakens the vessel walls. 

(B) Passive or venous hyperaemia occurs much more frequently 
than arterial hyperaemia. It is due to an abnormal obstruction 
to the outflow of blood from the veins of the pulp, being dependent 
upon local conditions. The obstruction is generally at the apical 
portion of the roots of the teeth, where the mechanical unyielding 
of the hard dentinal walls combined with the absence of a collateral 
circulation causes its development to the fullest degree. 

The microscopical changes in the pulp affected by venous conges- 
10 



146 THE DENTAL TISSUES 

tion, which will be presently fully described, may be summarized 
as follows: — A capillary and venous dilatation is followed by the 
organ becoming deeply reddened; the axial and peripheral blood 
streams in the veins become confused; the erythrocytes are densely 
crowded together; and stasis (the cessation of flow of the blood 
current) and emigration of the colourless blood cells supervene. 
The dilatation of the capillaries and veins arises from the loss of 
balance of the haemodynamic pressure caused by the lessened resist- 
ance of the blood stream to friction, through its slowing down. A 
transudation of liquor sanguinis through the endothelial walls 
is favoured and accelerated by the intra- vascular pressure; and more 
or less cedematous conditions quickly ensue, because of the absence 
of lymphatic vessels from the pulp. If these conditions remain 
unrelieved, acute inflammation takes place. 

SPECIAL HISTOLOGY 

Viewed from a clinical aspect, it may be stated that the com- 
mencement of caries is marked, as a rule, by one of two distinct 
types of lesions: (1) the not uncommon clean-cut cavity, which 
by its general appearance suggests erosion of the enamel and dentine; 
and (2) the usual cavity of " decay." The former is distinguished by 
its position on the cervical portion of the labial aspect of the anterior 
teeth, and by its intense hyperesthesia on receiving interrupted 
tactile impressions; the latter is recognised by its inability to trans- 
mit slight functional impulses to the pulp. Microscopically the 
difference between these two classes is well denned, the first-named 
particularly presenting marked deviations from the usual type. 

(1) The sub-enamel region of the dentine contains not only 
the usual dentinal tubes but also areas occupied by large inter- 
globular spaces, which are distributed with more or less regularity 
throughout its substance. Micro-organisms are present in enormous 
numbers at the margin of the cavity, and fill the tubules for varying 
distances. Opposite the breach of surface a corresponding deposit 
of adventitious dentine with enlarged irregular tubules is observed. 
The dentogenetic zone, that layer of tissue "on the borderland of 
calcification" is increased in thickness, and exhibits a greater 
quantity of calco-globular masses than normally. They are, how- 
ever, very small. In the pulp, slight hyperemia and cell prolifera- 
tion have certainly occurred in this locality and its neighbourhood; 
and the peripheral cells, which present many of the appearances 



DISEASES OF THE DENTAL PULP 



147 



of the so-called odontoblasts, are multiplied greatly. Beyond, the 
tissues may be considered to be normal, with the exception perhaps 
of the smaller blood-vessels, whose lumina are more or less increased 
in size. Rounded cylindrical deposits of newly formed but 
uncalcified dentine constantly exist in the central portions of the 




Fig. 163. — Hyperaemia of the pulp in situ. Prepared by the Author's process. 
Stained with Ehrlich's acid haematoxylene. Magnified 50 times, p. Pulp 
tissue; i.t. Inflammatory products; b. Enlarged blood-vessels; o. Odontoblasts 
D. Dentine. 



pulp, and point to a degenerative process. The changes from the 
normal to the pathological areas are very gradual, no sharp line of 
demarcation cutting them off from the other parts of the soft 
tissues. 

Referring to the statement just enunciated that "the so-called 



148 THE DENTAL TISSUES 

odontoblasts are multiplied greatly," it must not be inferred that 
these cells are merely numerically increased. They are profoundly 
modified, inasmuch as they now possess certain new characteristics. 
Their nuclei have become elongated and flattened, and are rendered 
very prominent when any of the nuclear stains have been used, and 
perhaps they are more granular than usual. The cell walls are 
indistinguishable, chiefly from the fact that each odontoblast is 
compressed laterally by its neighbours. In some instances they are 
gathered into sheaves, as in fibroid degeneration or atrophy of the 
pulp. Some observers might describe the appearances as being due 
to an indirect splitting-up of the cells: and it is not difficult to con- 
ceive of an odontoblast, when once fully formed, undergoing mitotic 
changes. In sections prepared by Weil's method, microscopically 
the tubules in the primary dentine below the breach of surface 
are unaffected by stains, and clearly differentiated from other tubules, 
having been, perhaps, fully calcified throughout their extent, and a 
band of altered pulp tissue may extend right across that organ. 

Thus, at the very outset, two most remarkable conditions attract 
attention. These are the multiplication of the numbers of inter- 
globular spaces, and also cytogeny of the so-called odontoblast cells — 
phenomena which are entirely absent from all ordinary conditions. 

There would, therefore, seem to be some connection between the 
subjective symptoms of pain and these fresh developments — or at 
all events one of these fresh developments — and this leads one to the 
conclusion that the degree of the sensitiveness of these cavities is 
dependent partly on the increase or diminution in the numbers 
of the interglobular spaces, and partly on the anatomical relation- 
ships which hitherto existed between the hard tissues. The author 
believes that the sensitiveness of these marginal cavities is due, in a 
great measure, to the actual exposure of the terminations of the 
dentinal fibrils, which is associated with that developmental error 
where the edge of the enamel and cementum do not meet, as they 
normally do boul a bout. 

Bodecker, 1 in speaking of dentinal irritation in the case of ordinary 
caries, attributes the sensations of pain to "alternate contractions 
and expansions of living matter" in dentine and enamel, "conveyed 
from the periphery to the centre of the tooth, these intense contrac- 
tions being induced by highly irritating agencies." 

But it must be remembered that it is only mechanical stimulation, 
at first, of the floor of these particular cavities that gives rise to pain; 

1 "Anatomy and Pathology of the Teeth," p. 288, 1894. 



DISEASES OF THE DENTAL PULP 



149 



and it must be inferred with greater accuracy in the light of present 
knowledge of the physiological stimulation of nerves and protoplasm 
generally, that the pathic disturbances are due here to direct impulses, 
which pass by means of the dentinal fibrils from the protoplasmic 
contents of the interglobular spaces to the ultimate telodendria 
of the sensory pulp neurones. 

The occurrence of additions to the numbers of the long odontoblast 
cells does not admit of quite so easy an explanation. The writer 1 
just quoted has indirectly noticed, although he has not figured 



b w 




Fig. 164. — Odontoblasts in acute inflammation of the pulp. Prepared 
similarly to the preceding. Magnified 230 times, o. Odontoblasts; d. Dentine; 
b.vv. Basal layer of Weil; p. Pulp tissue. 



this phenomenon. He says: — "The first change in the affected 
pulp-tissue is its reduction to an embryonal or protoplasmic state" 
— a statement which is certainly not verified on examination of 
properly stained microscopical preparations. Further, he proceeds : — 
"Should the lymph-tissue be reduced to its embryonal conditions 
as above indicated, the protoplasm present before transformation 
into basis-substance reappears, and may break up into odontoblasts 
or into osteoblasts. In the former case, the result of irritation of the 
pulp-tissue will be dentine, in the latter bone." The method of thus 

1 Op. cit. 



IS© 



THE DENTAL TISSUES 



interpreting the genesis of these lime-bearing cells is crude and 
illogical. 

The local increase in the numbers of the odontoblasts may demon- 
strate that, in certain situations, there is a greater need for the higher 
and more sustained exercise of their functions, these functions, 
probably, consisting mainly of shielding the delicate pulp from in- 
coming dangers; not by the production of dentine matrix, but by 
physiologically creating a larger or more concentrated area of trophic 
influence or control — if one may so speak — on the surface of that 
organ, whereby its vitality may be retained until the latest possible 




Fig. 165. — Acute inflammation of the pulp in situ. Prepared as in the pre- 
ceding. Magnified 130 times, d. Dentine; o. Inflamed odontoblasts; p. In- 
flamed pulp tissue; B. Small vein with axial current of blood corpuscles and, at 
the sides, emargination of the leucocytes. 

moment; or it may be that the odontoblasts have merely undergone 
mitosis. This is probably the correct view to hold. 

True formations of compact bone are most rarely found in the 
tooth-pulp; several cases, however, have been recorded (see pp. 68, 
69), but calcareous deposits are exceedingly common. 

Compact osseous tissue consists of Haversian canals, concentric 
and intermediary lamellae, lacunas, and canaliculi, with blood-vessels, 
osteoblasts, connective tissue, branched bone corpuscles, and minute 
lymphatic systems. (See Chap. VI, Vol. I.) And if these com- 



DISEASES OF THE DENTAL PULP 151 

ponent parts are non-existent, it is a mistake to pronounce the new 
formation bone. 

(2) Turning, in the second place, to cases in which the dentine 
is well developed and free from irregularities, the subjective pain 
symptoms do not, as a rule, appear until there is almost penetration 
into the pulp chamber, no matter how rapidly the carious encroach- 
ments may take place. But the pulp exhibits similar microscopical 
characteristics to those already detailed, the most obvious being 
cell-proliferation and odontoblast multiplication with isolated 
cylindrical calcoglobulin formations in the neighbourhood of the 
vessels. Regional hyperemia is often present — that is, the capil- 
laries, arteries, and veins are rather larger, have thinner walls, and 
are more tortuous than normal. 

Acute Inflammation 

Definition. — This is one of the terminations of hyperaemia, and 
also one of the results of dental caries. It is one of the commonest 
affections of the pulp, because of the anatomical peculiarities of 
the parts, and of the prevalency and numbers of its causes. Syno- 
nym: Pulpitis, a hybrid term. 

Etiology. — (i) Caries; (ii) The incautious use of drugs; (iii) 
Fillings of an irritant or thermal conducting nature; (iv) Trau- 
matism; (v) As an extension of inflammation from the alveolo- 
dental periosteum. The latter is septic in origin and occurs in teeth 
whose roots are more or less incomplete, and whose apical foramina 
are still very patent. 

Terminations. — Resolution, organisation, suppuration, or 
gangrene. 

Signs and Symptoms. — The Galenic signs of acute inflammation 
are manifested in the pulp as elsewhere, but vary greatly in inten- 
sity. Thus pain (dolor) is the greatest, whilst swelling and heat 
(tumor et color) owing to its circumscribed environment are the least. 
The pulp macroscopically becomes very red (rubor). The first is 
due to pressure upon the nerve bundles and the great tension pro- 
duced by the hyperaemia; and the others are due to hyperaemia, 
leucocytic emigration, serous exudation, proliferation of "fixed" 
tissue elements, and the relatively large amount of blood in the 
parts. 

GENERAL HISTOLOGY 

Inflammation is the complete local reaction of the tissues to in- 
juries and lesions of various kinds. 



152 THE DENTAL TISSUES 

"In recent years it has become more and more evident that the 
only theory which allows the full meaning of inflammation to be 
grasped, is the broad biological conception which recognises in in- 
flammation an adaptive protective, and reparative tendency com- 
mon to the reactions to injury among all animals." (Hektoen and 
Riesman. "A Text-book of Pathology," 1901.) 

To Cohnheim 1 and MetchinkofP belong the credit for a great 
deal of the early and late knowledge of this subject. " Inflammation 
brings into operation a number of factors to counteract harmful 
agents, protect the organism at large, and effect healing. The 
common mode of origin, the similarity of the changes (though 
combined in different proportions) and the evident tendency of 
the inflammatory processes to protect and repair, justify fully 
the teaching that inflammation is essentially an adaptive, protective, 
and reparative process, a means of self-preservation. Yet it must 
not be forgotten that the mechanism of defence and preservation 
is far from perfect; the exudate may possess but little bactericidal 
power; the phagocytes may be powerless, or the bacteria may 
multiply freely within them; extensive destruction of tissue may 
occur before the virulence of the bacteria is neutralised; the "fixed" 
cells may form imperfect material for repair or multiply in excess 
. . . The inflammatory reaction does not respect the relative 

importance of the tissues Hence, inflammation, though 

biologically an adaptive and preservative process, may appear 
harmful, requiring the intervention of medical art. Taking all 
things into consideration, we may conclude that inflammation is 
a reaction to local injuries, calling forth protective and reparative 
measures; but that it is an imperfect pathological adaptation, often 
leading to consequences that are dangerous per se and defeat its 
purpose." (Hektoen and Riesman. Op. cit.) 

As this is true for the tissues in general, so does it equally apply to 
the dental pulp in particular. 

It has been pointed out that passive or venous hyperemia may 
soon pass into a condition of inflammation. A brief sketch of the 
roles that are severally played by (a) the blood-vessels, (b) the 
colourless blood cells, (c) the exudate, (d) the "fixed" cells, and {e) 
the nervous system in this important condition must now be 
detailed. 

1 Cohnheim: Archiv fur Pathol. Anal., vol. xv, 1867, xxlv., i86g. 

2 Metchinkoff: L'Immunite dans les Maladies Infectieuses, 1904. Pathologie 
Comparative de PInflammation, 1891. 



DISEASES OF THE DENTAL PULP 1 53 

(a) The Blood-vessels. — It is believed that the vessel walls are 
structurally altered during the course of inflammation to allow of 
and facilitate the emigration of the blood cells and plasma. Their 
endothelial cells are contractile (Klebs) and, according to Metch- 
inkoff, mobile and phagocytic, and by frequently enlarging, cause 
an increased resistance to the vascular stream. 

(b) The colourless cells play a fundamental part in the process, 
by passing into the perivascular tissues, as first pointed out by Du- 
trocht in 1828. Cohnheim laid great stress on this phenomenon. 
Detaching themselves from the marginal current, which they nor- 
mally occupy on account of their low specific gravity, they become 
attached to the endothelial lining of the walls; and, as a result of a 
localised positive chemio-taxis produced by the diffusible products 
of bacteria, drugs, etc., emanating from the seat of the lesion, pass 
through the intercellular cementing substance. Leucocytic emi- 
gration is a complicated process, and varies with the nature of the 
cells actively engaged in it; thus there may be more eosinophiles 
than small mononuclear leucocytes, etc. The emigration is 
favoured by the dilatation of the blood-vessels and the contractility 
and mobility of the endothelial cells; and is determined by positive 
chemio-taxis by which the leucocytes advance toward the foci of 
greatest attraction. 

The erythrocytes follow the white cells at greater or shorter in- 
tervals of time. 

Phagocytosis is the action of certain leucocytes and wandering 
cells — with endothelial and "fixed" connective tissue cells to a lim- 
ited extent — which occurs in the presence of pathogenic bacteria 
and other particles of matter. A kind of intra-cellular digestion 
takes place, alexins — protective bactericidal bodies — being formed, 
either by a process of secretion, or as Hardy believes, excretion, 
and the adventitious material being destroyed. The function is 
carried out by the neutrophile cells, and the polymorphonuclear 
leucocytes, and also perhaps the mononuclear leucocytes. Negative 
chemio-taxis — the antithesis of positive chemio-taxis — means the 
insensibility of phagocytes to and their actual repulsion from the 
toxins present in any particular part. 

The inflammatory exudates possess also bactericidal properties, 
as shown by the experiments of Buchner, Nissen and others, and 
assist the phagocytes in their beneficial operations. All leucocytes 
are not phagocytes — eosinophiles are not; they possibly possess 



154 THE DFNTAL TISSUES 

excretory functions and may diminish the vitality of the 
micro-organisms. 

(c) The inflammatory exudates contain more proteids than 
physiological lymph, also fibrin, fibrinoplastin, etc., and certain 
digestive ferments and peptones. The quantity is very insignificant 
in the pulp tissue; the serous and sero-fibrinous and fibrous exudates 
are small in amount and poor in quality; but the hemorrhagic 
exudate, originated by the intensity of the primary lesion and due 
to an enormous emigration of the erythrocytes is very marked. 
After traumatic exposure of the pulp, during excavation of a deep 
carious cavity, for instance, where a thin layer of dentine remains in 
the floor, there is often a large flow of arterial and capillary blood, 
signifying extensive changes in, and injuries to the vessel walls and 
also a great quantity of haemorrhagic exudate. 

(d) "Fixed" Tissue Elements. — Retrogressive and progressive 
changes may go on side by side, but the former are more pronounced 
in the earlier stages of acute inflammation. Inflammation follows 
injuries that produce lesions not sufficiently great to induce com- 
plete necrosis and death of the part. No inflammation of the pulp 
is set up by cocaine pressure anaesthesia: it is anaesthetized merely. 
But in carious encroachments which give rise to an acute inflam- 
mation the pulp cells become greatly damaged and undergo 
extensive retrogressive changes. Necrosis and necrobiosis of 
the "fixed" cells and leucocytes occur. The odontoblasts at the 
site nearest to the lesion become fatty and degenerate; while further 
away they become "sheathed," and show signs of proliferation. 
This is probably an attempt on their part to heal the injury or pre- 
vent further damage from taking place, by warning the pulp, so 
to speak, of the oncoming dangers; and perhaps even to stimulate 
the dentine-depositing cells about them to functionate and pro- 
duce adventitious dentine. These phenomena will be presently 
further alluded to. 

(e) The sympathetic nervous system exercises a certain amount 
of influence in inflammation. Hyperemia and exudation are in- 
terfered with by the uncontrolled action of the vaso-constrictors, 
the toxins are not removed, and repair of the injury cannot be pro- 
ceeded with. If, on the other hand, the vaso-dilators exceed their 
functions, congestion takes place enormously or a strangulation 
of the vessels of the radicular regions chiefly soon leads 
to moist gangrene of the entire organ. 



DISEASES OF THE DENTAL PULP 



155 



SPECIAL HISTOLOGY 

Acute inflammation will be considered under two aspects:— 
(A) When caries has not penetrated into the cavity, and (B) 
when it has penetrated. 

A 

Conditions Associated with Non-penetrating Caries 

The odontoblasts, in the cervical regions, are enormously mul- 
tiplied in point of numbers and layers. The cells themselves 
are not enlarged, but possess prominent oval nuclei which are much 
flattened laterally. Interposed here and there are small, hitherto 




Fig. i 66. — Acute inflammation of the pulp, with masses of calcoglobulin in 
situ. Prepared as in Fig. 163. d. Dentine; p. Pulp tissue; b. Enlarged capillary; 
c. Calcoglobular mass. 

undescribed translucent globules, structureless and non-laminated, 
but similar in other respects to tiny calcospherite spherules (see 
Fig. 166). These are seen at the dentine border between the cells, 
and sometimes in Weil's layer. At the junction of the carious 
region with the primary or first-formed dentine the latest deposited 
dentine has, at its periphery, the globular appearances observed 
during developmental periods. It takes aniline dyes more deeply 



i56 



THE DENTAL TISSUES 




Fig. 167. — An early stage of chronic (?)inflammation of the pulp. Prepared as 
in Fig. 163. Magnified 30 times, d. Dentine; p. Pulp; b. Enlarged blood- 
vessel; o. Odontoblasts gathered into sheaves. 



DISEASES OP THE DENTAL PULP 157 

than the normal dentine, from which it is highly differentiated. 
This new tissue may be called "adventitious" dentine — a term 
which includes several varieties previously noted. At the places 
where the carious tubules open into this freshly deposited layer, 
the odontoblasts are considerably shrunken, and pressed inwards 
towards the pulp. They are disposed in one, or at most, two layers, 
and their peripheral poles (dentinal fibrils) are greatly enlarged and 
swollen. The layer of Weil, of adult pulps, is most marked here. 
Micrococci and bacilli infect the newly formed tubes, and in some 
places expand them. And where tubular expansion has been 
effected, there the odontoblasts are absent, their places being oc- 
cupied by a homogeneous mass of broken-down cells, with a few 
necrosed or necrobiotic nuclei scattered about. Active hyperaemia 
is distinguished by enlargement and tortuosity of the capillaries 
and arterioles, their engorgement with blood, and emigration of 
leucocytes (see Figs. 163 and 165). 

As the thin sheet of adventitious dentine gradually widens out, 
the odontoblasts become elongated, remaining all the time in one 
layer, their fibrils, each with its individual enveloping tube, being 
of normal size, and stretching across the new dentine at fairly 
regular intervals. The cells themselves are sometimes gathered 
into sheaves — a condition frequently noticed in degenerative 
changes (see Fig. 167). With the widening of the sheet of dentine, 
they become smaller and shorter, and diminish rapidly in number, 
until they disappear altogether. 

Meanwhile the adventitious dentine presents the well-known 
appearance of areolation almost identical with that of the inter- 
globular spaces. This areolar adventitious dentine has been de- 
scribed on p. 72. The structure of the pulp itself at this place is 
of the homogeneous character already noted. Thus the vessel 
walls are changed, the endothelial cells being enlarged and projecting 
into the lumina of the capillaries, and undergoing mitosis. The 
active movements of the emigrated leucocytes, which have already 
passed through the intercellular cement substance of the vessel 
walls, are directed to certain areas in the tissue through the influence 
of positive chemio-taxis set up by the diffusible products of the 
bacteria (bacteri-proteids) in the tissues, and of other substances. 
The serous or sero-fibrinous exudation is necessarily slight; and the 
fixed connective tissue cells of the pulp, having undergone cytogeny, 
suffer from retrogressive changes, and, becoming necrotic or necro- 
biotic, show signs of cloudy swelling, disintegration and death. 



is8 



THE DENTAL TISSUES 



The dentine which fills the cornua of the pulp exhibits irregular 
formations, as if deposition had taken place in a hurried manner. 
Not only are nucleated cells with long processes imbedded in the 
hard mass, but large lacunal spaces are frequent, each containing 
micrococci which have entered via the tubules of the primary dentine. 
In some instances this cellular dentine somewhat resembles the 
structure of sponge. 

A bacteriological survey of the same specimens of hypersemia 
and early stages of the lesions which Rothmann 1 has designated 




■ p 



Fig. 168. — Acute inflammation of the pulp. Stained with Ehrlich's acid 
haematoxylene and eosin. Shows the inflammatory products attracted to a 
focus of inflammation, p. Leucocytes and proliferated connective tissue cells; 
I.F. Inflammatory focus. 

"Partial acute pulpitis," and Wedl 2 "Pulpitis acuta partialis," 
furnishes one with some valuable particulars as to the probable 
distribution of the micro-organisms in the pulp and surrounding 
tissue. Miller 3 has isolated, cultivated, and named the most 
important of the cocci and bacilli; here is an opportunity of describ- 
ing the probable routes of their invasion of the pulp itself. 

The micro-organisms, after their introduction into the pulp 

1 "Patho-Histologie der Zahnpulpa und Wurzelhart," 1889. 

2 "Atlas zur Pathologie der Zahne," pp. 68, 69, 1893. 

3 "Micro-organisms of the Human Mouth," 1889. 



DISEASES OF THE DENTAL PULP 1 59 

cavity, are believed to make their way in chains, groups, or masses 
to the spaces between the odontoblast layer, the dento-genetic and 
ordinary pulp cells on the one side, and the border of dentine on the 
other; and also to the interpolar (interfibrillar) spaces, and the 
intercellular intervals. Thence they travel apparently to the basal 
layer of Weil, although here they are not congregated in such large 
or such numerous masses. Whatever their point of entrance, they 
soon pass to some considerable distance along the line of junction of 
the hard and soft tissues. 

Further, they are found in the substance of the pulp proper, 
chiefly arranged along the walls of the blood-vessels, in their inte- 
riors (when empty), and in the perivascular tissues. Infection of the 
nerve fasciculi most probably does not take place. The micrococci 
predominate largely over the rod-shaped organisms. The central 
and peripheral portions of the adventitious dentine are crammed with 
micro-organisms, but when the odontoblast fibrils with their sheaths 
cross the areolations of this new deposit, no bacteria can be found. 

From these investigations, therefore, it will be seen that, as a 
result, one is unable to coincide with Arkovy's theory of the phago- 
cytic function of the odontoblasts. 1 They certainly possess a granu- 
lar appearance, but a search for any micro-organisms which have be- 
come incorporated in the substance of their cytoplasm or nuclei is 
attended with negative results. 

If the course of the disease is progressive, inflammatory foci 
appear. These consist of proliferated connected tissue cells (macro- 
phages), pulp cells, and lymphocytes or polymorphonuclear leu- 
cocytes which have escaped from the numerous enlarged capillaries, 
all having been attracted together by positive chemio-taxis. The 
foci are very pronounced, commence at first in one or both of the 
cornua of the pulp opposite the carious dentine, and, as a rule, 
ultimately suppurate and form localised abscesses (Figs. 169 and 
170). Rapid destruction of the pulp ensues, and the undermined 
dentine finally gives way in the majority of cases. 

Sometimes a certain amount of fibrification of the cells lying in 
the immediate vicinity of the abscess occurs, and what might be 
termed a rudimentary abscess wall is developed. One is led to believe 
that this specialisation and grouping of spindle cells is not merely 
fortuitous, but a deliberate attempt on the part of the pulp to heal 
the lesion. The condition is observed in cases of chronic caries, the 
adventitious dentine being then deposited in layers, and presenting 

1 See Journal of Brit. Dent. Assoc, vol. xv., p. 602. 



i6o 



THE DENTAL TISSUES 




DISEASES OF THE DENTAL PULP 



161 




s~ -• -A 



162 



THE DENTAL TISSUES 



a characteristic fibrillar structure. On the border-line of the hard 
and soft parts, the connective tissue structure of the dentine matrix 
is well brought out. Islands of semi-calcified material in the body 
of the pulp suggest that they are nothing more nor less than calcified 
bundles of connective tissue fibres mixed with cells; the process 
of their formation being analogous to that of intra-membranous 
ossification of bone (see Fig. 170). 



B 

Conditions Associated with Penetrating Caries 

The exigencies of the scope of this book afford these notes oppor- 
tunity of speaking of. no more than two phases of one of the com- 




Fig. 171. — Inflammation of the pulp. The odontoblasts have been torn 
away from the surface of the dentine, to show the presence there of the proliferated 
connective tissue cells, leucocytes, and other products of the inflammation. 
Prepared by the Author's process. Stained with Ehrlich's acid haematoxylene. 
Magnified 180 times, d Dentine; p. Pulp tissue; o. Odontoblasts; I. Inflam- 
matory cells, etc. 

monest conditions found in the mouth, viz., idiopathic exposure 
of the pulp. 

In sagittal sections of teeth affected by acute caries, which has 
terminated in acute inflammation and partial suppuration of the 
pulp, it is obvious that the cells appear degenerate altogether. 



DISEASES OF THE DENTAL PULP 



163 



Connective tissue cells are broken down, the pulp cells have become 
changed into indifferent cells with large square nuclei, and escaped 
leucocytes crowd the tissues. Even the odontoblasts themselves at 
the cervical region are metamorphosed into short cells with rounded 
nuclei, and at the coronal part are opaque, and seem to have under- 
gone fatty or mucoid degeneration (Fig. 172). 

Finally, at the periphery of the pulp the small globular deposits, 
already mentioned, are found. The nerve bundles have lost their 
definite structure, and though retained in position are evidently less 




Fig. 172. — Acute inflammation of the pulp. Prepared and stained as in the 
preceding figure. Magnified 80 times, d. Dentine; p. Pulp tissue crowded 
with inflammatory products; o. Odontoblasts. 



translucent and more disorganised. There are no clear evidences 
of fatty degeneration in the sections under notice, although Wedl 1 
describes this as existing in his sections of acute purulent pulpitis. 
The tissues are greatly condensed at the margins of the abscess 
cavity, the cells being short and fusiform, and interlacing closely 
with each other. The blood-vessels are hyperaemic, and micrococci 
and bacilli are abundantly distributed throughout the tissue. 

The last condition which will be here considered is that of a phase 
of acute partial suppurative inflammation of the pulp, in which 

1 Op. cit., p. 71. 



164 THE DENTAL TISSUES 

that organ has been subjected to the devitalising action of arsenious 
acid for a period of not less than twelve hours. 

In addition to appearances which denote the intensity of the 
inflammation — hyperaemia, marked cellular infiltration, suppuration 
and other changes common to acute inflammations in soft tissues — 
a prominent feature is a large special form of dentinal deposit which 
is situated at the base of the carious opening into the pulp chamber. 
This is cellular and hyaline adventitious dentine previously described 
on pp. 72 and 74. 

This particular form of cellular or hyaline adventitious dentine 
does not occur solely in acute inflammation of the pulp, it is also 
seen in chronic inflammation with hyperplasia ("polypus") near 
the lower portion of the pulp cavity. In this case it may be accom- 
panied by new dentine which has a pronounced laminar structure. 

In conclusion, a study of the patho-histology of these lesions leads 
one to the following deductions: — 

(1) That nearly every degree of dentinal change is attended 
with hyperaemia, and cell proliferation in the pulp tissues, and gener- 
ally speaking, the formation of adventitious dentine: 

(2) That the latter may have its origin as a conversion or secretion 
of the dento-genetic cells, producing on the one hand the areolar or 
laminar or hyaline varieties, when the formative cells alone happen 
to be concerned; on the other, the fibrillar or cellular forms when 
odontoblasts or connective tissue cells are by chance incorporated 
in the deposit: 

(3) That the new dentines, by a system of extension from the 
affected areas, may be just as much subjected to the peptonising 
action of micro-organisms as the primary dentine of the tooth. 

Chronic Inflammation 

This is sometimes one of the sequelae of acute inflammation. 
The pathological processes are essentially the same. The changes, 
however, are continuous, thus: The dilated vessels remain in a 
condition of dilatation and lose their tone, leucocytes continue their 
work of emigration through the vessel walls, and the original tissue 
cells still further proliferate. 

Etiology. — The causes are similar to those of the acute conditions; 
but certain general systemic diseases such as rheumatism, gout, 
hydrargyrism, etc., are believed to be powerful, predisposing, and, 
in some cases, exciting causes. 



DISEASES OF THE DENTAL PULP 165 

HISTOLOGY 

It is nearly always associated with the formation of large masses 
of calco-globulin nodules in the pulp, and may go on until the whole 
of the pulp tissue becomes converted into a hard calcareous mass. 

When there is exposure of the pulp, these deposits of calco- 
globulin are always seen in the region of the inflamed area. They 
are irregular in shape, and often attain a large size, and fill up the 
pulp tissue. Sometimes these dentine masses extend throughout 
the pulp like long rods running parallel with the walls of the pulp 
chamber. The pulp, when removed from its cavity, is found to be 
stiffened and hard from the presence of these calcified rods. They 
are seen in the immediate neighbourhood of the blood-vessels and 
nerve bundles. 

When stained, for microscopical purposes, they behave like the 
dentogenetic zone in developing teeth — that is they take fuchsine, 
haematoxylene, carmine, and other stains very intensely. 

If there is an extensive exposure of the pulp, the tissue often 
undergoes productive inflammation, and becomes hyperplasic, and 
the condition known as polypus is found. 

Hyperplasia of the pulp is a chronic productive inflammation, 
in which the redundant material formed is extruded through the 
opening at the base of the carious cavity. At first small, it slowly 
increases in size, until ultimately a large soft fungating mass fills 
up the cavity, and sometimes overhangs its edge. It must be 
diagnosed from hypertrophy of the gum, the two points of difference 
being usually easily determined. 

Hyperplasia of the pulp is probably caused by the irritation of 
sharp dentinal margins of the pulp cavity, which become slowly 
absorbed as the condition advances. 

The patho-histology is interesting. The mass consists briefly of (i) 
a superficial epithelial layer, (ii) a stroma or frame-work of strong 
fibrous tissue, (hi) supporting the large granulation-like cells and 
blood-vessels, which constitute the greatest parts of the growth. 

(i) The superficial epithelial covering consists of a stratified 
layer or layers of large squamous epithelial cells. The occurrence of 
squamous epithelium in the surface of a tissue which does not 
normally contain any epithelial cells is remarkable. This auto- 
plasty was formerly believed to be due to a form of skin-grafting 
brought about by the transference to the free surface of the exposed 
pulp of portions of epithelial tissue from the mucous membrane of 



1 66 



THE DENTAL TISSUES 



the cheek, during the act of mastication. The truth is that the 
surface cells of a portion of gum which overlaps an edge of carious 



EA 




Fig. 173. — A large fungating hyperplasia of the pulp overhanging the edge of 
a carious cavity. Stained with haematoxylene and eosine. Magnified 230 
times. D. Normal dentine; E. Edge of carious cavity, c. Cementum; p. Pulp 
tissue; e.a. Epithelial-like areas in pulp. 

dentine rapidly proliferate as a result of the mechanical irritation, 
and spread over the exposed portion of the pulp to which they 
finally become firmly adherent. 



DISEASES OF THE DENTAL PULP 



167 



The periphery of the growth may present one or two different 
structures. (1) It generally consists of very flattened non-nucleated 
cornified squamous epithelial cells, with little intercellular cement 
substance. (2) The periphery may closely copy the ordinary 
epithelial characteristics of the mucous membrane of the mouth 
and gums, that is to say, its sub-mucous surface, is thrown into 
innumerable folds or papillae. 

In the first instance several thin layers of epithelial cells, arranged 
as strata, sometimes may be found. The outer layers are composed 




SW' 



te& 



m 



'■"Wag**-* <J($*^ 



' "' ". 






^ 






• ' * ^ * ' 



y> 







%r 



Fig. 174. — Chronic inflammation of the pulp, with hyperplasia of that tissue 
(so-called "polypus"). Prepared as in the preceding figure. Magnified 250 
times, b. Blood-vessel crowded with corpuscles; c. Nuclei of the inflammatory 
cells. 

of flat cells, the inner of ovoid cells, generally two or three rows. 
Each cell is granular. Finally, there appears the stratum Malpighii, 
where the cells are smaller and columnar in shape with oval nuclei. 
These rest on the papillae, a sort of basement membrane dividing 
them from the general sub-mucous tissues beneath. The papilla 
found in the second instance are conical elevations projecting 
into the layer of the rete Malpighii. If they are undivided they 
are known as Simple; if they are beset with smaller papillae they 
are called Compound. They consist of compact fibrous tissue. 
The rest of the "polypus" proper consists of a fibrous stroma, 



1 68 THE DENTAL TISSUES 

in which the fibrous tissue is very pronounced, firm, and interlacing 
in all directions. In the meshes of this reticulum are found large 
granulation cells, some round, some square, and each having a 
large nucleus (see Fig. 174). 

The capillaries terminate at the periphery, and run amongst 
the meshes of the stroma. At its attachment to the pulp cavity. 
the fibrous tissue is arranged in strong bands which stain a deep 
yellow colour with picric acid. The blood-vessels in this portion are 
scanty, but larger than those seen at the periphery. 

Here also rounded masses of laminar adventitious dentine are 
found. They have a laminated nature, one or two small cells 
occasionally occupying the interior of the pulp nodule. 

In the pages of UOdontologie of September 15th, 1902, Pont 
describes an extremely curious neoplasm of the pulp which is almost 
unique in the annals of Dental Pathology. 

Under the title of "Note sur un cas de Tumeur de la Pulpe 
dentaire sans carie de la dent," an account is given of this anomaly, 
occurring in the second maxillary right premolar of a man of 35 
years. He complained of pain. An enamel chisel removed the 
occlusal surface of the tooth which was perfectly sound, and revealed 
a "soft, deep red, easily torn, but not painful growth of the pulp, 
which had produced absorption of the cavity walls." It was 
extirpated easily, the operation being unattended by much 
haemorrhage. 

A histological examination having been made by Dr. Charvet, 
of the Faculty of Medicine, of Lyons, this gentleman reports that 
it was not a tumour properly so-called, but probably a simple inflam- 
matory condition of the pulp. He wrote as follows: — 

"La piece a. examiner, n'a nullement le caractere d'une tumeur. 
Sur les coupes colorees au picro-carmin, on trouve des traces de 
travees sclereuses, et dans tous les points, des nappes de cellules 
inflammatoires; ailleurs enfin des hemorragies interstitielles plus 
ou moins etendues. Nulle part il n'y a de masses neoplasiques, 
ou pouvant y faire songer. II semble s'agir d'un bourgeon charnu 
inflammatoire en voie d'organisation sclereuse." 

Infective Gangrene of the Pulp 

These chemical and biological changes proceed very rapidly. The 
first stage begins as a post-mortem change, and does not necessarily 
depend upon the presence of Schizomycetes, the fact being that both 
the liquid and solid constituents of the pulp immediately after 



DISEASES OF THE DENTAL PULP 1 69 

its death are capable of destroying many micro-organisms. The 
changes partake more of the nature of a chemical dissolution than 
a result of bacterial infection, and are dependent upon the action 
of the unformed soluble ferments found in the pulp, as in other soft 
tissues. These soluble ferments or enzymes are present in all 
living tissues, and have much to do with the processes of metabolism. 
Thus albumen becomes converted by these enzymes into peptones 
and hemi-albumens. 

Pathogenic bacteria are capable of developing in the soft tissues 
and bringing about the changes just mentioned. But in or- 
der that they may develop sufficiently to produce these chemical 
changes in sufficient amount before they themselves are destroyed, 
there must be some local focus of disease or area of chemical 
decomposition present, which becomes largely invaded by pus- 
forming micro-organisms. 

It is therefore obvious, that if the balance between the biological 
actions of the invading and invaded forces is maintained in equi- 
librium, simple death of the pulp will occur; that is, its general 
functions will cease, its physiological resistance to disease or injury 
will be in abeyance, its powers of undergoing progressive or further 
retrogressive metamorphoses will be terminated, and it will remain, 
perhaps for many years, an inert, innocuous, ineffectual remnant 
of its former self — pale and shrunken. The hard parts surrounding 
it will, at the same time, be affected by the loss of nutrition, and 
the enamel — probably through changes in the subjacent dentine, 
certainly not through actual alteration of its own structure or 
chemical composition — will eventually become dark and lustreless. 
This is what happens in the case of a tooth which has been "killed" 
by a blow on the mouth. 

On the other hand, if the bacterial infection is great and the 
albuminoid bodies thus produced are voluminous in amount, 
toxic enzymes result. These are very active poisons, which give 
rise in a short space of time to the usual chemical products of 
decomposition, viz., carbonic acid, ammonia, sulphuretted hydrogen, 
and certain other salts and water. The evolution of these is de- 
pendent upon the access of oxygen, heat, and moisture. 

According to Buckley {Trans. Fourth International Dental 
Congress) the chemical changes of putrefaction are those of hydra- 
tion, reduction, and oxidation. In the first, there is a taking-up 
of one or two molecules of water, in the second, a breaking-up 
and decomposition by nascent hydrogen, and in the third, the 



170 



THE DENTAL TISSUES 



formation of carbonic acid, acetic, nitrous, nitric and similar acids. 
Other substances manufactured simultaneously, in varying degrees, 
are globulins, toxic enzymes, peptones, the nitrogenous amino-acids, 
leucin and tyrosin, the nitrogenous amines, methylamine, pro- 
pylamine, etc., and organic and fatty acids such as formic, propionic, 
butyric, valerianic, palmitic and other fatty substances and also 




Fig. 175. — Vertical section of infective gangrene of the pulp removed from 
its containing cavity. Stained by Gram's method. Magnified 45 times. 
M. Dense masses of micro-organisms; p. Non-infected pulp tissue. 

putrescine (C4H12N2), and the isomers cadaverine and neuridine 
(C5H14N2). These latter become quickly converted into ammonia 
and its derivatives. Thus is the pulp destroyed, and it is probable 
that the contents of the dentinal tubes are also similarly filled with 
the end-products of decomposition. 

The Pathogeny of Gangrene of the Dental Pulp 

A frequent termination of inflammation, whether traumatic 
in origin or not, is gangrene, or mortification of the pulp. The 



DISEASES OF THE DENTAL PULP 171 

patho-histology of this condition has been studied by Dr. Fritz 
Schenk, of the Dental Department of the University of Vienna. 
An interesting article from his pen appears in the Oesterreichisch- 
ungarische Vierteljahrsschrift fur Zahnheilkunde, for March, 1902. 
The following are some of his important observations. 

"At the apex of the pulp a gangrenous mass, entirely devoid of nor- 
mal tissue elements, is found in the earliest stages of the disease. 
A line of demarcation cuts this off from the healthy portions of the 
organ, and contains disintegrated cells. In the gangrenous re- 
gion, as has just been stated, no cells or tissue fibres can be recog- 
nised, but in fresh gangrenous patches fat globules, formed by a 
process of dissolution, appear. Micro-organisms are present in 
this situation, according to Miller, Arkovy, and Scheff. This con- 
dition corresponding to Rothmann's " Pulpitis gangrenosa chronica," 
has also been investigated by Witzel and Arkovy. This gan- 
grenous patch is surrounded by the "line of demarcation." The 
rounded contours of nuclei may sometimes, especially if a solution 
of eosine be used as a staining reagent, be noticed at the borders of 
this patch. Their chemical characters may be altered, and indi- 
cate a "transition stage" towards final dissolution. In the neigh- 
bourhood of the non-gangrenous portion the nuclei decrease in 
number; and this together with the passive hyperaemia present con- 
stitutes the chief signs of the "line of demarcation." 

"In the remaining tissue, which generally borders on the 
gangrenous portion, and is in course of inflammation, there is one 
factor to be especially noted, that besides migrated red blood- 
corpuscles in the tissue, the vessels appear enlarged, sometimes 
filled with coagulum. The appearance may be seen, both in longi- 
tudinal and in transverse sections, only at the line of demarcation; 
nearer to the gangrenous portion the vessels are entirely missing. 

"The termination of an inflammatory process in the pulp often 
leads to gangrene, which does not cover the whole or major portion 
of the pulp, but generally only includes at first the distal parts. 
From this point it proceeds towards the centre. For the conclusion 
of the process there is needed a longer or shorter period; therefore 
this process has been correctly designated Pulpitis gangrenosa 
chronica. 

"Contemporaneously with this course, certain phenomena also 
occur in the tissues, which lead to the destruction of the pulp. 
These processes likewise develop comparatively slowly. 

"In the first place one process regularly occurs in such pulps, 



172 THE DENTAL TISSUES 

the importance of which in all inflammatory conditions is to be 
specially emphasised. The red blood-corpuscles secede from the 
coagulum contained in the enlarged vessels. One observes them 
lying everywhere freely about in the tissue. Especially remarkable 
is this at the line of demarcation, where the colouring can be seen 
macroscopically or with the magnifying glass. 

"When the nutrition of the protoplasm of the cellular tissue 
reaches abnormal conditions, as is the case with inflammation of 
the pulp, it may easily happen that in the protoplasm there super- 
venes coagulation of its albuminoid constituents, which may be of 
a fibrino-plastic nature. This view in regard to coagulation (Alex. 
Schmidt) is here adopted. 

"If coagulation of the protoplasm has once occurred, every 
function within it which is necessary for the preservation of the 
cellular tissue is made difficult in performance, and the cell must 
therefore go through a retrogressive metamorphosis, which finally 
leads to degeneration. Furthermore, the general law is also of effect, 
that ihe protoplasm of the tissue elements has a certain connection 
with their nuclear formations. 

"Consequently, both morphological constituents of the cell — 
the protoplasm as well as the nucleus — are indivisible and inde- 
pendent, in order to manifest the vital function of the cell. The 
nucleus is a necessary attribute of the cell, and becomes its dominant 
constituent, inasmuch as it governs its growth. It undergoes 
mitosis, and influences the histological differentiation. The nuclei 
produced by the fission resemble the mother-nucleus (O. Her twig). 
Portions of protoplasm, without nuclei, may maintain themselves 
for a time, however, without multiplying. 

"Many portions of protoplasm are incapable of fulfilling their 
physiological functions as soon as the nucleus has disappeared from 
them. Leucocytes, whose protoplasm possesses qualities of life 
and movement, but whose nuclei are not divisible, die, and remain 
in the living organism as pus corpuscles. 

' The protoplasm which is fitted to absorb material from the 
surroundings, and to make corresponding use of it, loses all the 
qualities peculiar to it through the coagulation of its albuminoid 
bodies. Through this coagulation it not only loses the power to 
absorb materials and to convert them, but, furthermore, it is no 
longer capable of phagocytic functions. 

" In this manner it can be easily explained that in chronic gangrene 
of the pulp the first impulse for its origin is given by the coagulation 



DISEASES OF THE DENTAL PULP 1 73 

of the protoplasm of the cellular tissue. It is the primary affection, 
in the wake of which follow the other appearances of gangrene. 

"The alterations of the nuclei appear only when the protoplasm 
has lost its vitality through the coagulation of the albuminoid 
bodies. By this means the relationship between the nucleus and 
the protoplasm entirely ceases. The nuclei become smaller, and 
gradually lose more and more of their karyoplasm, and decrease 
in size until they have shrunk to dot-shaped remnants of the chro- 
matic substance. Finally these also disappear, and one only sees 
circumscribed, light, uncoloured portions in the decayed granular 
gangrenous substance, which possibly still exist as the last remains 
of the former nuclei. It is true that the cell nuclei exhibit a longer 
power of resistance during this pathogenic process than all the other 
tissue constituents of the pulp, but at last their individual recognis- 
able morphological elements disappear, and with them the dignity 
of being able to act in the regeneration of the elements." 



CHAPTER VI 

INJURIES OF THE DENTAL PULP 

Microscopical Elements found in: (i) Methods of healing after 

wounds of the pulp. 

GENERAL CHARACTERISTICS 

Of all the morbid conditions usually associated with the dental 
pulp it is generally conceded that those reparative processes which 
occur after injury or during the course of a disease of that organ 
rank first in interest and importance. A study of the methods by 
which nature attempts to repair or heal a lesion is, on careful con- 
sideration, one of the most fascinating subjects that can engage the 
attention of the pathologist. If this is so generally, in the great 
domain of general surgery and pathology, how much more interest- 
ing to dental surgeons, must be a study of a like nature when con- 
nected with that most delicate organ the dental pulp? 

It is not at all surprising that this is a structure which possesses 
great recuperative powers, and is constantly exercising its functions 
in this respect by undergoing repair. Very seldom indeed can a le- 
sion of the soft or the hard parts of a tooth occur without a corre- 
sponding attempt — more or less successful — on the part of the pulp 
to ward off its attacks. For in the exercise of its highest functions 
it is concerned with the maintenance of the vitality of the tissues 
in the centre of which it is placed. Hence any invasion by disease, 
or the occurrence of an accident is succeeded by a resistance which 
in many cases is highly satisfactory, and the tissues are not devital- 
ised. Probably nearly every dentinal change is accompanied by some 
healing process of the pulp. 

The restoration to a normal condition of pulp lesions partakes of 
the characteristics both of those of the soft parts, like a wound of the 
skin or other vascular tissue, and those of bones, as in the case of 
fracture. Instead of a permanent or definitive callus being formed 
in the pulp cavity, the conditions are modified through the anatom- 
ical peculiarities of the part: and, as a result, the various kinds of 
adventitious dentines, already fully described, occur. It is unnec- 

i/4 



INJURIES OF THE DENTAL PULP 1 75 

essary to lay stress on the fact that here, as elsewhere, the process is 
essentially similar. Osteoblasts, which are the great factors in the 
production of bone, are not found in the pulp; but the dento-genetic 
cells, with which the tissue is freely supplied, do similar work. When 
the pulp is nearly exposed, for instance, they combine to repair the 
damage done by caries. Examples of "dentine of repair" are often 
seen. In traumatism, too, the process is exactly the same as when 
a tissue has been wounded, and has been kept in an aseptic condition, 
and properly protected from certain infective processes. In these 
cases the method of repair is known as "healing by the second inten- 
tion," or granulation. A third, but exceedingly rare class of cases, 
where a tooth, having been fractured, and the parts kept at rest 
until union has been effected, supplies an example of "healing by the 
third intention." Cemental or dentinal union is only possible, it is 
obvious, when pulp or periodontal membrane, or both, have received 
an injury which has not destroyed their reparative powers, but which 
has induced a slight or sub-acute form of inflammation, and thus 
stimulated the active cells to perform their functions. 

These notes, however, are not intended to generalise altogether, 
but to particularise, and to sum up what is known of some of the 
healing processes in the pulp. 

It will be convenient, then, to consider the subject from several 
points of view; — (1) When a minute area of the pulp tissue has been 
injured; (2) when a large surface has been traumatically exposed; 
(3) ordinary exposure of the pulp by the action of caries; (4) frac- 
ture of teeth with or without impaction of the fragments; and finally 
(5) in cases of non-exposure of the pulp. 

HISTOLOGY 



When a minute area of the pulp has been injured. 

It is not difficult to conceive of a simple traumatic inflammation 
of the pulp being set up when a small traumatic exposure has been 
made, which has been immediately followed by the penetration (and 
therefore wounding) of the soft tissues by means of a fine point like 
that of a bristle. The picture that can be drawn of this rather hy- 
pothetical state of things is quite clear, from one's knowledge of 
wounds generally. 

The capillaries, together with the small arteries and veins in the 
coronal region, would be divided, causing momentary hemorrhage, 



176 



THE DENTAL TISSUES 



which soon ceases in consequence of stasis and coagulation of the 
blood. Dilatation of the vessels in the neighbourhood with relaxed 
flow of their blood-currents next supervenes, leucocytes and liquor 
sanguinis escape from their walls, and the cellular elements around 
undergo sub-division and proliferation. Lymph in minute quantities 
is poured out, and contains fibrin and blood corpuscles; the serum 
becomes absorbed and approximation of the divided surfaces 
results. Outside the region of the wound the vessels are dilated, 
but the rate of the flow of blood is increased. Shortly after the 




Fig. 176. — Coagulation necrosis and fatty necrobiosis of the superficial por- 
tions of the pulp occurring after a chemical injury of twelve hours' duration, 
following a sub-acute inflammation of the pulp. Stained with haematoxylene 
and eosine. Magnified 200 times. 

injury, the exudate, which has coagulated, more or less, is removed 
and replaced by small round cells derived from the infiltrating leu- 
cocytes and proliferating connective-tissue cells, and thus adhesion 
of the separated parts takes place. Finally, delicate loops of new 
capillaries emanating in their origin from the old vessels spread across 
the parts, and anastomosing, restore the vascularity of the tissues, 
and repair the lesion by the production of fibrous bands and ulti- 
mately a small cicatrix. 

Such a condition of things could only be accomplished when the 
pulp was only slightly injured; when the foreign body producing the 



INJURIES OF THE DENTAL PULP 1 77 

injury was not septic; and when the cavity in the dentine had been 
treated by strictest antiseptic measures. 



When a large area of the pulp surface has been traumatically 
exposed, as occurs during fracture of the crown of a tooth in an 
attempted extraction, regional hyperaemia occurs and inflamma- 
tory symptoms are set up. Many interesting microscopical struc- 
tures are now brought to light. 

If sections are made within twelve hours of the accident — or rather 
if the preparation of the tissues for section cutting is begun within 
twelve hours — the pulp will be found to be crowded with small round 
cells. These comprise the infiltrating leucocytes and proliferating 
connective-tissue cells. The odontoblasts are profoundly altered 
in shape, being flattened and compressed on to the dentinal walls 
through the swelling and exudation of the inflammatory processes. 
They have also undergone mytosis and are numerically multiplied. 
The vessels are actively hyperaemic, and in the radicular portions of 
the pulp are largely thrombosed. On the free surface of the pulp 
an attempt at healing has occurred, organisation of the exudative 
fluids and materials having taken place. Blood cells, escaped from 
the broken coronal capillaries, are caught and retained in the 
meshes of a fine fibrous stroma of new formation. The cells are very 
greatly disintegrated, and probably many of them have been con- 
verted into pus corpuscles. Probably, too, coagulation necrosis 
and fatty necrobiosis of the superficial tissues have, to a certain 
extent, taken place, as there are some appearances of fibrin forma- 
tion as well as degenerative lipogenesis in the midst of the tissues 
(see Fig. 176). It is unlikely that micro-organisms would produce 
liquefaction of the parts in so short a space of time as twelve hours, 
especially as a thick blood-clot would have protected the free surface 
from the oral secretions. It is almost certain that if liquefaction of 
the necrotic tissue and the solid exudates has occurred it is due to 
proteolytic enzymes. 

On examining sections where a similar lesion had occurred seven 
days previously, but few fresh changes are noticed. The free 
surface is covered, as before, with many layers of disintegrated 
cells, including pus cells. Traces of the original inflammation have 
more or less disappeared and new capillaries abound, freely vascu- 
larising the part. But one notices everywhere, and especially in 



i 7 8 



THE DENTAL TISSUES 



the cervical and radicular regions, new deposits of soft calcific ma- 
terial in the midst of the tissues. These have the same appear- 
ance as that shown in Fig. 170. The laying down of calco-globulin 
is a favourite method of repair on the part of the pulp. Whence 




Fig. 177. — Freshly deposited calcific nodules in the pulp, showing the method 
of formation. Prepared by the Author's process. Stained with borax-carmine. 
Magnified 50 times, p.d. Primary dentine of the tooth; N. Formed and calcified 
dentine nodules incorporated in the walls of the pulp cavity; f.n. Nodule formed 
but not yet calcified; F. Connective fibrous stroma with dentogenetic cells, about 
to form the'calcified masses; p. Pulp tissue with nerve bundles and blood-vessels; 
A. Pulp near apical region. 



F N 



come these new masses? How are they brought into existence? 
What laws govern their formation? These are questions which 
one finds considerable difficulty in answering satisfactorily. It is 
unlikely that they are due to the local enzymes of micro-organisms. 



INJURIES OF THE DENTAL PULP 



179 



or that they are found congregated around masses of bacteria. They 
are not always dependent on being closely approximated to vessel 
walls, for they are seen in other situations. Black 1 inclines 
to the belief that the formation of these masses is due to a condi- 
tion of congestion or venous hyperemia of the pulp. He compares 
them to the phleboliths found in varicose veins, and suggests that 
in these congested veins there may exist the three conditions, or 
factors, necessary for the production of calcospherite globules. 



M N 



FN 



C T F 



C i 




Fig. i 78. — An early stage in the formation of nodules of calcific material in 
the pulp. Shows methods of formation. Prepared as in the preceding figure. 
Stained with orange rubine. Magnified 250 times, f.n. Nodule undergoing 
calcification; N. Nuclei of the formative cells; C.T.F. Connective tissue fibres; 
m.n. Myelinic nerve bundle; c. Capillary; p. Pulp tissue proper. 



viz., the presence of carbonic acid in association with salts of lime 
and albumen. Similar views have been recently expressed by Wood- 
head in a paper on Calcification. 

It seems probable and possible that these nodes are produced 
solely by the pouring out of calcific matters by the dentogenetic 
cells of the pulp, which take on a catagmatic function identical with 
that of the osteoblasts in the formation of callus. It is probable 
that this phenomenon occurs in the case of the growth of "pulp 

1 "American System of Dentistry,'' voi. i., p. 862. 



180 THE DENTAL TISSUES 

nodules" and during calcareous degeneration of the pulp. And 
if so there, why not here? 

That the process must be somewhat of this nature would seem 
to be confirmed by the interesting case fully reported by C. S. Tomes, 
and published in the Transactions Odonto. Soc. of Great Britain, 
pp. 184-5-6, 1896. Of such importance this would apparently be, 
that no excuse is needed to here add Tomes' description. The 
tooth, a mandibular molar, had been fractured during attempted 
extraction three years before removal of the root. The pulp cavity 
was then seen to be occupied by a "cauliflower-shaped mass of 
shining polished ivory projecting above the original surface of frac- 
ture and overflowing on to it." The pulp was only partially cal- 
cified, the lowest radicular portion containing sentient tissue. The 
large mass of newly formed material was closely coherent to, and 
contiguous with, the old dentine. 

Histologically speaking, a cursory inspection of its structure 
showed a free surface with laminae running parallel with the sur- 
faces. A series of lacunal spaces came below, then a few dentinal 
tubes, and finally in the deepest portion, numerous dentinal tubes 
which were, in some places, continuous with the tubes of the pri- 
mary or original dentine. The outgrowth of hard tissue contained 
embedded in it several detached and displaced splinters of the 
primary dentine. 

The following are details: — 

"The Laminated Outer Layer. — This consists of laminae parallel 
with the surface, and varies in thickness reaching in places )250 
inch, and containing about ten well-marked layers. Here and there 
it constitutes the whole of the overflow, and it contains some canal- 
iculi, taking a direction perpendicular to the surface, and a few 
well-formed lacunae with their canaliculi. It is present every- 
where, though its amount and the distinction of the lamination are 
variable. 

" The Lacunal and Interglobular Spaces. — The tissue immediately 
below the laminated layer is characterised by an immense number of 
lacunae and interglobular spaces, which are in parts well formed, and 
in other parts very coarse and irregular. The fine boundary of this 
region of lacunal spaces is in places well defined, and terminates 
with bodies of the "encapsuled lacuna" type; elsewhere it passes 
insensibly into the region occupied by tubes, in the outer part of 
which latter region interglobular spaces are abundant, and are 
somewhat irregularly disposed. 



INJURIES OF THE DENTAL PULP l8l 

"The Tube System. — In the centre of the tooth the tubes, like 
those of normal dentine, run vertically upwards towards the surface, 
while towards the sides of the new mass they radiate outwards, 
passing thus beyond the limits of the fractured primary dentine, 
and spreading themselves fanlike over the edges of the original 
tooth to a certain extent. In that portion of the newly formed 
dentine which lies within the original dentine, and which latter 
constituted originally the lateral walls of the pulp cavity, the 
tubes run more or less outwards, and are joined up into con- 
tinuity with the old dentinal tubes, there being generally an abrupt 
bend and some dilatation at the junction. From an inspection of 
the sections it will thus be seen that the whole boundary of the 
resultant pulp cavity, formed at its sides and below by the original 
dentine, and above by the new dentine, is formed of dentinal tubes 
of normal appearance, and that the pulp, though diminished in 
bulk, has almost perfectly normal surroundings over nearly its 
whole area. 

"As the tubes run outwards they become more widely separated 
owing to their fanlike spreading: it is noteworthy that there are not 
a greater number of tubes in the expanded portion, but that the 
interstices between them become larger. A good many lateral 
branches are given off, such as those which occur abundantly in the 
dentine of roots of normal teeth. Towards their outer extremities 
many of the tubes show longitudinal dilatations, and are joined up 
to the canaliculi of lacunal spaces; some end in brush-like expan- 
sions, while others terminate in loops, the loops being common to two 
or more tubes; others are sharply bent back on themselves. At and 
above the ends of the tubes fine globular formations may here and 
there be very distinctly seen. 

" The Included Splinters of Dentine. — As has already been mentioned 
this specimen is probably unique in that the newly formed dentine 
contains quite a number of little detached pieces of the original 
dentine of the tooth which were splintered off in the original attempt 
at extraction, and which have become solidly enclosed in the new 
formation. They have been displaced in various ways so that their 
tube systems run in all sorts of directions, and are in no way con- 
formable with the tubes of the new growth. But they have in their 
irregularity of position, this much in common, that the tubes of the 
new growth when they are of any size, do not pass beyond them, but 
terminate beneath them. To this, however, there are some excep- 
tions, where quite small chips appear to have been driven more 



182 THE DENTAL TISSUES 

deeply into the pulp. Upon the whole, then, it may be said that the 
broken fragments of old dentine either lie embedded in the region 
of lacunal spaces, or between this and the commencement of the 
tube system. It is not a little remarkable that none of the frag- 
ments show the least sign of absorption, but that their edges are 
left quite angular, just as if they were broken off. Where the tubes 
commence close against the fragments, they are bent about, obviously 
with relation to the included pieces. 

"Marks of Absorption. — It is notable that notwithstanding the 
violent irritation to which the pulp was subjected, in very few places 
can any marks of absorption be found. "The occurrence of 'en- 
capsuled lacuna-like' forms has already been mentioned where the 
lacunal region merges into that of well-formed tubes, but a few marks 
of absorption and subsequent calcification are to be found elsewhere 
and in unlikely places. Thus under the calcified overflow are some 
pits occupied by Howship's lacunae." 

Here is a history of the injury extending over a period of three 
years — it is not a question of hours or weeks; and so it would appear 
that the two cases previously quoted might, had time been allowed 
and all conditions favourable, have succeeded in developing into 
complete calcification of the pulp, not by the conversion of blood-clot 
or organisation of the inflammatory products necessarily, but simply 
by a conversion, or secretion or excretion of the lime-bearing cells of 
the pulp into one united mass; in other words, the calcification of a 
plastic exudation. It is true that no cell of this description has ever 
been seen depositing this material in the form of calco-globulin; but 
it is quite easy to understand that as a result of pathological changes 
in the dentine, these small cells may be stimulated to exercise their 
functions of abstracting the lime salts from the blood in the pulp, 
manufacturing them again in the cell-cytoplasm, and ultimately 
pouring them forth when their work is done. 

3 
Again, exposure of the pulp through caries leads, as is well known, 
to inflammation. This may be so severe as to cause death of the 
pulp, whose unyielding environment prevents much swelling and the 
free discharge of accumulated inflammatory products. Restorative 
processes are, however, often brought about, and the result is the 
formation of a so-called "polypus" of the pulp. The term "poly- 
pus" is an incorrect appellation, and as such ought to be deleted 
from dental terminology (see page 165). 



INJURIES OF THE DENTAL PULP 1 83 

The formation of a protective covering by the extension and 
growth of squamous epithelial cells on the free surface of the exposed 
tissue must certainly be considered as another attempt at healing, 
and might almost be a modification of autoplasty. For chronic 
inflammation of the pulp, with an epithelial surface, may, and often 
does, remain in a carious tooth for months and years without any 
discomfort to the individual. Probably the reparative process is 
most complete when the new tissue assumes the form not merely of 
several layers of stratified squamous epithelium, but dips down into 
the granulations and gives to their surface the shape of simple or 
compound papillae. This produces a thicker envelope, and affords 
greater protection to the soft subjacent structures. 



Perhaps, after all, the methods of healing of wounds of the pulp 
are better illustrated in cases of those fractures of the teeth where the 
parts have been kept in situ for some period of time subsequent to 
the accident. And one may cite, in addition to Tomes' unique 
specimen, three more cases which have been recently reported. 

In the first-mentioned patient — a girl, aged 14 — an incisor was 
fractured longitudinally and impacted. It was thought that union 
would be established either through the medium of the pulp or 
periodontal membrane. Here, however, probably from the mo- 
bility of the fragments, the pulp became inflamed, fungated, and 
finally calcified. Thus healing of the pulp lesion occurred, although 
union of the hard parts was not established. 

In a second interesting case several features were noticed. The 
tooth, also a maxillary incisor, was not impacted, and there was no 
ultimate union. Under the microscope the margins of the pulp 
canal showed traces of absorption, Howship's foveolae being 
strongly pronounced. These areas of absorption were filled with a 
layer of new dentine, which at the extreme apex of the root was 
homogeneous — like the matrix of hyaline cartilage — and cellular, 
higher up, an intermediate kind of irregular fibrillar dentine inter- 
vening. The pulp at the free margin of the upper fragment was 
enlarged and chronically inflamed, being unusually fibrous in 
character. How can the presence of these new dentines in the root 
canal be interpreted? Obviously, a healing process, which, if 
allowed to continue, would have finally obliterated it with a hard 
mass of new dentine. 



1 84 



THE DENTAL TISSUES 





Figs. 179 and 180. — Outer halves of an impacted united maxillary incisor. 
The sagittal section, from which Fig. 181 is taken, was the central portion of the 
tooth. These and the three following photographs are from specimens in the 
collection of F. J. Bennett. 




Fig. 181. — Sagittal section, showing the parts, e. Enamel; d. Dentine; p. Pulp 
cavity; o. New ossified material which acted like a definitive callus.' 



INJURIES OF THE DENTAL PULP 



l8 5 



The case presented somewhat similar features to that of another 
case of impacted fracture of a canine, save that in the latter the 
calcified uniting portion was the product, most probably, of the 
cells of both pulp and periodontal membrane, a genuine example of 
autoplasty. 

This specimen was one of profound interest. 

The history showed that an oblique fracture of a tooth and im- 
paction of one of its fragments had remained in situ for ten months. 
Intense pain led to its ultimate removal from the mouth. 




Fig. 182. — Low power magnification of the intervening uniting tissue. 

The fragments were united by some dense calcified material 
which spans the intervening space (see Figs. 181, 182 and 183). 
The margins of the space were uncalcified. The catagmatic ma- 
terial consisted of spongy or cancellous osseous substance, freelv 
supplied with blood-vessels. The edges of the primary dentine 
showed signs of absorption and subsequent deposition of a cemen- 
tum-like material. 

The probable explanation of the pathological changes which pro- 
duced such an excellent union may be described as follows: — It 
is "a case in which, haemorrhage having taken place, a natural cap- 
ping of the exposed pulp occurred, somewhat similarly to the way 



i86 



THE DENTAL TISSUES 



a wound heals under a scab. Blood was poured out between the 
fragments, organisation took place, numerous blood-vessels were 
produced, and ultimately calcification occurred; and, eventually, if 
it had been left long enough, the whole of the space would probably 
have been filled up with calcified material more or less resembling 
bone, or bone and cementum together" (Trans. Odonto. Soc. of 
Great Britain, April, 1896). 

Finally (5) little need be said here with regard to the last di- 
vision of this subject, viz., those cases of non-exposure of the pulp, 




Fig. 183. — Higher power of the same. 



because the question has been discussed in the preceding Chapter, 
and, it may be added, is still incompletely investigated. Suffice it 
to draw attention to the fact that the inroads made by caries in the 
dentine and enamel is counter-balanced in the pulp by the produc- 
tion of several different kinds of adventitious dentine, and that 
both early and later lesions of the hard parts are nearly constantly 
associated with the development of new dentines, and, therefore, 
with one of the most interesting methods of repair of the tissues 
of the pulp. 



CHAPTER VII 
THE DEGENERATIONS OF THE DENTAL PULP 

Microscopical Elements in: — (i) Fibroid; (ii) Atrophic; (iii) Fatty, and 
(iv) Calcareous Degenerations. 

GENERAL CHARACTERISTICS 

As a result of various conditions, the pulp is exceedingly liable to 
undergo degenerative changes. The most common is calcareous, 
because of the great tendency for this organ to repair any breach of 
its surface, which has been made by carious or other morbid processes. 

If a tooth has persisted for years, and has withstood all attacks of 
a traumatic, chemical or carious origin, its pulp will, under favourable 
circumstances become sclerosed and fibrillar, if not, it will probably 
undergo calcareous or other atrophic changes. It is necessary to 
consider these conditions somewhat in detail: — 

i. Fibroid degeneration. 

2. Atrophic degeneration. 

3. Fatty degeneration. 

4. Calcareous degeneration. 



Fibroid Degeneration 

Whilst studying the histology and histo-pathology of the dental 
pulp in its normal relationship to dentine, and preparing sections of 
human teeth with this object in view, the author found among his 
sections some excellent and remarkable examples of fibrosis or fibroid 
degeneration. The typical appearances presented on microscopic 
examination of these specimens warranted more than a passing notice : 
and as they were further investigated, they became more and more 
interesting, sufficiently justifying an accurate description and a care- 
ful account being placed on record. 

Definition. — Later it will be clearly shown that the term "fibrosis" 
or fibroid degeneration is the only one which can with certainty be 



i88 



THE DENTAL TISSUES 



applied to this particular form under notice. That it is an example 
of degeneration there is no doubt, and it is equally easy to eliminate 
those other degenerative varieties — such as mucous, calcareous or 
fatty, which animal tissues may undergo. 




Fig. 184. — Vertical section of fibroid degeneration of the pulp in situ. Pre- 
pared by the Author's process. Stained with acid rubine. Magnified 45 times. 
d. Dentine; p. Pulp tissue; s. Circular spaces cut longitudinally; f. Dense strands 
of strong coarse fibres. 



Etiology. — The present instance affords an opportunity of ex- 
amining certain structural metamorphoses in the pulp which are 
believed not to be dependent on any inflammatory condition, but 
simply attendant on and produced by senile constitutional changes. 
Further investigations will go to prove that it is a natural old-age 
termination of the life of a healthy pulp. 



THE DEGENERATION OF THE DENTAL PULP 



189 




FO 



Fig. 185. — Fibroid degeneration of the pulp of a deciduous tooth. Stained 
with haematoxylene. Magnified 45 times, p.d. Primary dentine; a.d. Hyaline 
adventitious dentine; a. Absorption of primary dentine; f.o. Fibroid odonto- 
blasts; b. Blood-vessel; n. Nerve bundle. The degeneration is complete at the 
lower part of the figure. 



190 THE DENTAL TISSUES 

This affection seems to have been unknown to, or overlooked by 
the dental pathologists of the Continent and America, for though 
Arkovy, Magitot, Rothmann and Black, publish minute descriptions 
of the patho-histology of the dental pulp and periosteum, and 
elaborate dissertations on ulcers and tumours connected therewith, 
in no instance does one find an account of the senile variations in the 
tissues of a tooth. Black, in the "American System of Dental 
Surgery" (Vol. i., p. 859), figures and describes an areolation of the 
pulp, which at first sight resembles fibrification of that tissue, but 
differs very materially from it in the fact that numerous cells and 



d o 




Fig. 186. — Fibroid degeneration of the pulp. Prepared and stained as in 
the preceding figure. Magnified 250 times, d. Dentine; d.o. Degenerate odon- 
toblasts; p. Pulp tissue proper. 

nuclei are present in the sections from which he draws his conclusions. 
He writes: — "Areolae develop in the matrix, and all the histological 
characters of the tissues are profoundly changed. These areolae 
were evidently filled with fluid; hence a kind of oedema of the organ 
must have existed, which, in the enclosed pulp-chamber, has prob- 
ably gradually destroyed the cellular elements; and new elements 
thrown out in the inflammatory process, have suffered the same 
fate." 

Of the pathology and clinical histories of the teeth, the histology 



THE DEGENERATION OF THE DENTAL PULP 191 

of which is presently to be described, little need be said. The teeth 
from which the sections were taken were chiefly maxillary canines 
and premolars, apparently sound, but useless, inasmuch as they had 
been loosened by the gradual absorption of their alveolar bone, 
which had left the portion below the neck exposed. As a result, 
there had occurred that peculiar periostitic pain, or something 
analogous, so often noticed in elderly patients with absorbed sockets, 
and the teeth were extracted. They occurred in the mouths of 
different patients. Of a dark yellow colour, they presented, in 
addition, all the appearances of the changes of senility. 

Similar conditions in the deciduous teeth of children have been 
noticed. 

A good number of longitudinal and transverse sections, suitable 
for microscopic examinations, were obtained. The revelations af- 
forded by these sections are of a particularly interesting nature. 

Secondary Changes. — None. 

HISTOLOGY 

It is evident that in complete pulpar fibrosis no cellular elements of 
any description whatever occur. This is clear at once, and is an 
important fact. No trace of cellular organisation, no vestige of 
cell nuclei, no remains of interstitial cement substance can be found 
anywhere. Nerves, cells, blood-vessels, odontoblasts, have alike 
shared the process of fibrification, and are no longer recognisable, 
and the connective tissue, which is but a loose mass of network in the 
normal state, has either become grossly hypertrophied or quite oblit- 
erated, and its place taken by a new, firm, fibrous structure, devoid 
of cells, nuclei, or any regular arrangement of constituent parts. 

In a longitudinal section which is viewed under low magnifica- 
tion, the appearances much resemble pulmonary tissue, minus 
cells. The pulp seems to consist of retiform connective tissue, 
containing large alveolar spaces, with here and there long cylin- 
drical cavities, all having extremely thin walls. Several of these 
tubes are shown in Fig. 184; they are probably the fibrous remains of 
what once were blood-vessels. The dentinal surface of the pulp is 
occupied by a more highly defined appearance. Rows of long, thick 
fibres of various shapes and sizes, some bifurcated, others plain, and 
again some possessing fibrous off-shoots, are here distinctly seen, 
attached to, and in places detached from the dentine. In those 
situations where the fibres adhere, curious dark markings, extending 



192 



THE DENTAL TISSUES 




Fig. 187. — Horizontal section of fibroid degeneration of the pulp in situ 
Prepared and stained as in Fig. 184. Same magnification. D. Deeply stained 
dentine; s. Large areolar spaces; d.o. Degenerate odontobasts; p. Fibroid tissue 
of the pulp. 



THE DEGENERATION OF THE DENTAL PULP 1 93 

in the direction of the lines of the tubules, are visible in the dentine; 
they are, without doubt, due to the retention, in situ, of the dentinal 
fibrils, which give to them a different refractive index to that of 
the empty tubes. These are well demonstrated in the sections from 
which Figs. 184 and 186 are taken. The row of fibres represents 
the pre-existing odontoblasts. This is proved by the following 
points: — (1) They distinctly occur at the edge of the pulp, in the 
site occupied normally by the membrana eboris; (2) They are con- 
tinued into the tubules of the dentine, in a similar manner to that 
of the processes of the odontoblasts; (3) At the coronal portion of 
the pulp, the fibres are larger, stronger, more marked, and less nu- 
merous than elsewhere; and (4) Their method of attachment to 
the main parts of the pulp closely approximates to that which ob- 
tains in the normal odontoblasts. Hence it is that these fibres, 
with their marked outlines, are degenerate and fibroid odonto- 
blasts, but so altered in shape and size as to appear to be merely 
bundles of connective tissue, which penetrate the dentine to a vari- 
able extent. 

On examining transverse sections, several curious formations are 
noted. First, it is observed that there may be considerable fi- 
broid shrinkage of the pulp, and separation from one side of the pulp 
cavity, as in Fig. 187, or not so much atrophy as in Fig. 188. In the 
first instance, it is perfectly obvious that this shrinkage has not been 
caused by the mode of preparation to which the tooth was subjected; 
it is a natural and fibroid contraction of the pulp, produced by a 
gradual knitting-together of the fibrous tissues, which have become 
on one side detached entirely from the hard dentinal wall, in conse- 
quence of the unyielding nature of the latter. A large conspicuSus 
chain of areolar spaces is, however, the most striking object here ob- 
served (Fig. 187). It stretches without break, across the pulp 
chamber from side to side, and consists of groups of more or less 
circular empty spaces, bound together thickly by fibrous tissue. 
The vacuoles vary greatly in size: the largest measures about 220^ 
in its greatest length, and i6om in its greatest width, whilst the small- 
est here seen, which is also almost circular in shape, measures 
from 5-iOAi in diameter. At first sight these appear to be blood- 
vessels cut transversely, but such is not so, as they do not possess 
their distinctively characteristic walls, neither are they of the same 
or even approximate diameters. They are, therefore, simply long 
cylinders with thin but tenacious boundaries. No attempts at 
calcification can be distinguished in them anywhere; the stroma in 



194 THE DENTAL TISSUES 

which they are held is very dense, has a clear fibrous structure, be- 
comes very marked in staining, and consequently is highly differ- 
entiated from the surrounding tissue. 

It is probably extreme cases only that exhibit so remarkably 
the chain of areolae. Earlier stages seem to indicate that the fi- 
brosis originally began in the central portions of the pulp, in the vi- 
cinity of the arterial and nervous systems, and that the region of 
the basal layer of Weil and the odontoblasts were the last to undergo 
the metamorphosis, as the cells at the periphery of the pulp are the 




Fig. i 88. — Fibroid degeneration of the pulp. A slightly earlier stage than 
the preceding. Prepared similarly. Stained with Ehrlich's acid ha^matoxylene. 
Magnified 15 times, d. Dentine; d.o. Degenerate odontoblasts; a. Circular 
areolar space; p. Fibroid pulp containing no cells, no nuclei, no nerve bundles nor 
blood-vessels. 

last to retain their shape and nuclei (see Fig. 188, which repre- 
sents an incompleted stage of this form of degeneration). 

Degenerate odontoblasts are always clearly visible on the edge 
of the pulp. 

It is worthy of note that the lumina of the dentinal tubules 
are in no way narrowed or occluded by any adventitious varieties 
of calcification. 

It must not be imagined that these conditions are to be demon- 
strated in every senile tooth. Dentine nodules, atrophy, total 



THE DEGENERATION OF THE DENTAL PULP IQ5 

disorganization, and a number of other pathological states may be, 
and are often met with: there must be many aberrations from the 
types here considered. But, given teeth which have been healthily 
preserved through all the vicissitudes of life, unattached by extrinsic, 
and unexposed to intrinsic influences, it would seem that the above 
results are one form of the natural and usual termination of the 
life-history of the dental pulp. 

The causes of this condition are discussed in Chapter IX (q. v.). 

2 

Atrophy of the pulp 

This rare condition has been described and figured by Wedl. 1 
It is interesting from a microscopical point of view, but clinically 
it is indistinguishable from other senile changes. 

HISTOLOGY 

Here a reticulum fills the pulp cavity; the odontoblasts in early 
stages are shrunken; if the atrophy has far advanced they will 
have disappeared. The capillaries freely anastomose, and present, 
in places, marked varicosities due to the contraction of the connec- 
tive tissue stroma. They are larger than usual, and have thin 
walls. No nuclei in their sheaths can be seen. 

The nerve sheaths are fatty, granular, and in places deposits 
of lime salts cover them. The tissue in parts is naturally stained. 
This is due to escape of the colouring matters of the blood. Rounded, 
elliptical, or cylindrical deposits of dentine frequently exist in the 
body of the pulp tissue. 

Otto Walkhoff, in describing the photomicrographs of atrophy 
of the pulp in his "Atlas of the Pathological Histology of the Human 
Teeth," says that the condition may be limited to the odontoblast 
layer, vacuoles being found in the midst of the normal healthy tissue. 
At the same time, the underlying pulp tissue has become condensed 
and permeated with cells, the vessels are considerably dilated, and 
presumably indicate the extent of the alterations which the organ 
has experienced. Frequently the odontoblasts fuse into sheaves 
or layers, so that they can no longer be individualized (see Fig. 
212). The pulp tissue proper exhibits numerous globular spaces, 
and there is accompanying reticular atrophy. 

1 "Atlas zur Pathologie der Zahne," Plate IV. Leipzig, 1869. 



I96 THE DENTAL TISSUES 

And Armin Rothmann (op. cit.) describes a sclerosed atrophy 
of the pulp ("Atrophia pidpa scleroticans") which is apparently 
a stage, like the preceding, proceeding to its complete fibrosis. 
Thus, the normal connective tissue fibres — fine, delicate, and inter- 
lacing — have become coarsely fibrillated, and a simultaneous 
diminution in the number of the cellular elements has occurred. The 
fibres arrange themselves in narrow layers, which surround the 
calcific deposits in the sclerosed connective tissue. As the minute 
calcareous concretions increase in size, through fresh peripheral 
deposition, so do they form confluent masses of a bright granular 
material. 

3 

Fatty Degeneration of the Pulp 

Etiology. — This is said to be found in senile teeth, deciduous 
teeth which are undergoing absorption, and in teeth the pulps of 
which have been "capped." 

Macroscopical Appearances. — To the naked eye the pulp appears 
to have diminished in size, receded from the margins of the cavity, 
and of a pale reddish-gray colour. 

HISTOLOGY 

Fat globules are observed, when examined by the microscope, 
following the course of the capillaries and nerves, whose walls and 
sheaths undergo degenerative lipogenesis. 

The odontoblasts are degenerated, and have become mucoid 
or fatty. 



Calcareous Degenerations of the Pulp 

These are very frequent accompaniments of inflammation of this 
organ as has already been seen; but they frequently exist also in 
apparently sound teeth unaffected by caries. It is generally believed 
that a deposition of calcific material is found in the pulps of elderly 
people, and, as such, is Secondary Dentine. But it is often found 
in early adult life, and in youth, in sound teeth extracted for regula- 
tion purposes. The degenerations have been divided into two 
classes: 1st, in which the new material is unattached to the walls 
of the pulp cavity, and 2nd, where it is attached. 



THE DEGENERATION OF THE DENTAL PULP 



107 



i st. — The unattached deposit of the lime salts, a condition which 
may be known as calcification of the pulp, may take the form of 
nodules or rods. Nodules are said to be common in the teeth of 
gouty patients, in senile teeth affected by fatty degeneration or 




Fig. 189. — Longitudinal section through the pulp of a deciduous molar show- 
ing calcareous degeneration. Stained with hsematoxylene. Magnified 45 times. 
D. Dentine; o. Odontoblasts; V. Venule; c. Capillary filled with erythrocytes; 
M. Masses of calcific material. 



reticular atrophy, and in teeth which have been for a lengthy period 
subject to attrition or abrasion. They may exist in apparently 
healthy teeth, in which cases, their exact origin is extremel} doubtful. 
A pulp nodule originates in the centre of the pulp, close to the 
vascular system (Figs. 190 and 192). 



198 



THE DENTAL TISSUES 



HISTOLOGY 

Its true structure is revealed by the aid of the microscope. Under 
low powers, Figs. 190 and 191, one observes small, solid, rounded, 
highly stained masses occupying the centre of the tissue, placed 
between the vascular and nervous systems. They inconveniently 
crowd on the nerve bundles, and if allowed to increase by fresh 
external depositions, will gradually cause a mechanical lateral 
pressure on these nerve bundles and induce pain. Under higher 
magnifications the nodules are seen to be made up of matrix and 



C H 




P N 



Fig. 190. — A small pulp nodule in the radicular region of the pulp. Mag- 
nified 15 times, p. Pulp in situ; p.n. Pulp nodule; d. Dentine;. h.c. Hyper- 
plasia cementum. The section was prepared by Sidney Spokes. 



cells. The former is practically homogeneous in many sections, 
but it may be laminated or have a distinctly fibrous structure. It is 
generally rounded or lobulated in outline, and has ragged edges in 
sections prepared by the author's method. Nodules which have 
been isolated from the pulp have usually smooth outlines (Fig. 195). 
The cellular elements of these nodules are interesting. Roughly 
speaking, two varieties of cells are discovered, round, nucleated 
small cells, and long fusiform or spindle-shaped cells, with small 
nuclei. These, intimately mixed together, are distributed through- 
out the mass, but at the edges they are chiefly noticeable, giving a 



THE DKG ENERATION OF THE DENTAL PULP 



199 



P N 




Fig. 191. — Sagittal section through a human permanent canine tooth removed 
on account of mal-position. From a young patient. Prepared by Weil's 
process. Magnified 45 times. Shows four pulp nodules in situ. e. Enamel; 
D. Dentine; p. Pulp tissue; p.n. Nearly structureless pulp nodules. Note. — 
The specimen had remained in Grenacher's alcholic borax-carmine for a period of 
several years, with the result that the fine tubes in the nodules were stained by 
long immersion in the colouring reagent. 



200 



THE DENTAL TISSUES 




Fig. 192. — The formation of the pulp nodules. Prepared by the Author's 
process. Magnified 230 times. P.x. Pulp nodules; M.N. Myelinic nerve bundles; 
p. Pulp tissue; c. Capillary. 



PN 




P N 



Fig. 193. — Longitudinal section of a pulp containing two large pulp nodules, 
parts of which are shown. Stained with haematoxylene. Magnified 45 times. 
p.n. Nodules showing striations; c. Capillary; N. Myelinic nerve fibres. 



THE DEGENERATIONS OF THE DENTAL PULP 



20I 



rough uneven outline to the nodule (Figs. 192 and 194). The presence 
of the cells in the interior of the nodule is not constant. 

Having studied these depositions of lime-salts under many 
conditions, and possessing sections which exhibit various stages in 
their development and growth, the author has come to the con- 
clusion that they are formed by a secretion or conversion of the 
small round cells of the pulp (Fig. 194). This process may end in 
the total obliteration of the cell-wall and nucleus, or the cell itself 
may persist in situ. In some sections the odontoblasts have been 




d z 



M 



Fig. 194. — The method of construction of the dentine of a pulp nodule. Pre- 
pared by Weil's process. Magnified 250 times, d. Formed and calcified 
dentine; D.z. Dentogenetic zone; R. Round cells forming the dentogenetic zone; 
p. Pulp tissue. 



caught and embedded in the new dentine when it is attached to the 
primary or first-formed dentine. Of course, in the centre of the pulp, 
odontoblasts are non-existent, and consequently are never found 
embedded in the mass. Moreover, they are never seen round its 
margins. 

The fusiform cells are entangled in the secretion which seems 
to have flowed round them. They, too, undergo obliteration. 
Sometimes these completed pulp nodules remind one of the cal- 
cospherite spherules found occasionally in the normal tissue of the 



202 



THE DENTAL TISSUES 



periodontal membranes of young teeth. When quite complete, 
they may be more or less laminated, may be quite structureless, 
or may have a few fine tubes radiating from the centre outwards. 
These tiny tubes have been probably produced by the long fusi- 
form cells. 

It has just been stated that pulp nodules are invariably solid. 
This is not, however, quite correct. 

The accompanying photomicrograph (Fig. 196) shows that 
sometimes a pulp nodule may contain a pulp chamber in its interior. 
An example of this occurred recently in the practice of Mr. Neville 




Fig. 195. — A pulp nodule isolated from the pulp. Shows its central nuclear 
formation and its concentric lamination. Prepared by grinding. Magnified 
50 times. (From the collection of G. W. Watson.) 



Davis. Three teeth were removed from the same mouth, on account 
of excruciating and incurable pain. The pulps contained the 
largest nodules probably on record. One of them measured in 
width 2.5 mm. and in length 10 mm. Extending in the central 
axis of the nodule is a canal filled with ordinary pulp tissue. In 
one section the outermost part of the nodule consisted of fine-tubed 
orthodentine which gave the growth a conical shape. Inside this 
and filling up what at one time must have been the pulp cavity, 
was a mass of calcareous material, with still a small amount of 



THE DEGENERATIONS OF THE DENTAL PULP 



203 



C M 




Fig. 196. — A pulp nodule in situ, containing an axial cavity filled with a 
calcified mass resembling hyperplasic cementum or compact bone. Prepared 
by Weil's process. Magnified 12 times, p.n. Pulp nodule; CM. Calcified ma- 
terial occupying its interior; p. Pulp tissue; d. Dentine;H.c. Hyperplasic cemen- 
tum; J. Point of junction of pulp nodule with the primary dentine of the tooth. 



204 



THE DENTAL TISSUES 



pulp tissue remaining. The central hard mass contained a granular 
matrix, in which were embedded great numbers of lacuna? and inter- 
globular-like spaces. Here and there a few scattered dentinal tubes 
radiating centripetally were arranged in bundles. Such cases have 




\ 



Fig. 197. — A pulp nodule fused to the parieties of a pulp cavity. Prepared 
by grinding. Magnified 15 times, p.m. Pulp nodule; d. Dentine of the tooth. 
(The section was lent by J. F. Colyer.) 

never been described before; but they are probably not unique. 
(Fig. 196). 

One or more nodules may exist in the same pulp. They are 
oftenest located in the coronal or cervical regions, but occasionally 
may be found, as in Fig. 190, near the apical portion of the root 
canal. 



THE DEGENERATIONS OF THE DENTAL PULP 205 

Occasionally a pulp nodule may be attached to the wall of the 
pulp cavity. This has been brought about by new dentine from 
the margin of the pulp cavity, increasing and gradually encircling 
the nodule. 

2nd. — Attached deposits of dentine are generally seen in the 
coronal or cervical portions of the pulp (Fig. 197). They are 
associated at times with its hyperaemia and inflammation or, at 
times, any condition, like erosion, caries, etc., where there have 
been pathological changes of the dentine. 

Where they are due to the latter and there is a breach of surface, 
they represent the condition named by Salter, "dentine of repair/' 

Generally speaking, these new masses of dentine include many 
varieties. Thus they may differ but little from normal fine-tubed 
dentine — the tubes perhaps being finer and less evenly distributed. 
They may be almost structureless; again they may contain a few 
nucleated cells, or spaces which closely resemble interglobular 
spaces. 

In aged teeth, the pulp may become partially or completely 
calcified. Long rods of calcific material run longitudinally through 
its substance, and, in time, fuse and ultimately obliterate all traces 
of soft tissue (see Fig. 89). 



CHAPTER VIII 

THE PATHOLOGY OF THE PULP IN RELATION TO 
CLINICAL DENTAL SURGERY 

Introductory — Carious lesions — Lesions due to Tactile, Thermal, Chem- 
ical and Electrical stimulations — Referred Pain and Obscure Reflex 
acts — Receptivity of the Pulp: Its Hyperaesthesia and Dysa;thesia — 
Phases of Degeneration. 

INTRODUCTORY 

The above subject is of vast importance to the Dental Surgeon, 
but unfortunately at present only partially developed. The reason 
why it is only partially developed lies chiefly in the fact that the 
microscopical technique associated with its study is so tedious to 
accomplish, and sometimes so uncertain in its results, that it does 
not appeal generally to the worker in dental histology in spite of 
there being ample clinical material and ample scope for research. 
No thoughtful reader can for an instant deny the immense impor- 
tance to the dental surgeon which attaches to the subject, especially 
to one who has lofty ethical ideals and who practices his art in its 
most conservative forms. All the systematic knowledge of .diseases 
of other organs of the body which we possess — except, perhaps, 
those relating to myology and osteology — the morbid conditions 
of the blood-vessels, of the nervous mechanism, of the cellular 
system, wholly or in part, simple or complicated as they sometimes 
are, focus themselves on that minute structure in a tooth which 
we call the pulp, which is physiologically and in very truth the 
marrow of the tooth. 

THE DENTAL PULP ANALOGOUS TO BONE MARROW A PERFECT 

ORGAN 

There is not so much known about pathological conditions of the 
marrow of bones generally, but one probably does understand in a 
measure some changes which the marrow of a tooth has undergone 
when subjected to local or constitutional disturbances. And this 
is not at all surprising when one begins to realize that it is a perfect 

206 



THE PULP IN CLINICAL DENTAL SURGERY 207 

organ in a way, with its small arteries, veins, capillaries, and myelinic 
and amyelinic nerve fibres and cells whose functions are partly 
odontoblastic in nature, and partly are closely associated with the 
sensory nervous apparatus — a perfect organ situated on the terminal 
fringe of that complicated tangle of sentient fibres, the largest 
cranial nerve, the Trigeminus. It is on this fact and on all that it 
implies that the importance of the pulp depends, and that makes 
its conservation above any other dental tissue of the supremest 
moment. It would be futile on the part of the author to marshal 
in review the pathological conditions of which the pulp may be a 
victim These can be found in preceding chapters. This chapter, 
although it does not advance any novel or startling hypothesis, is 
designed to be suggestive rather than assertive, argumentative rather 
than dictatorial. In other words, de donner a penser a quelqu'un, to 
indicate possibilities, and to chronicle one or two sidelights which 
seem to have some bearing on the pathology of the organ. 

The subject may have been approached in two ways. On the 
one hand, it may have been considered strictly from the point of 
view of the association of certain signs, and subjective and objective 
symptoms and treatment, with the morbid conditions of the pulp; 
or on the other hand, the diseases and degenerations of this organ 
might have been systematically and histologically described, and 
linked in thought with certain clinical aspects of dental surgery. 

(I.) Carious Lesions 

DIFFICULTIES IN ELUCIDATING CERTAIN PROBLEMS 

The author wishes it had been possible for him to have stated 
clearly and satisfactorily what happens to the pulp and surrounding 
parts when obtundent drugs have been placed in a carious cavity; 
what takes place when antiseptic solutions are used, what physical, 
chemical, physiological, or pathological changes are induced when 
the various filling materials have been, for a given length of time, 
brought into contact with enamel and dentine. 

A perusal of the papers of Miller and Truman which appeared 
in the Dental Cosmos for 1890 and 1895 respectively, and a search 
through subsequent literature, serves to show the incompleteness 
of our knowledge of perhaps the most important and most common 
condition of things, viz., the exact results which occur in the daily 
mechanical and chemical treatment of diseases of the vitalized 
dental tissues and of the effects of dead bodies on living substances. 



208 THE DENTAL TISSUES 

The meeting-point of the dead and living is indeed a mystery. 
It is, of course, admitted that many facts are known about these 
things. James Truman published in the Dental Cosmos for January 
1895 a most interesting account of his work "On the Relative 
Penetrating Power of Coagulants." In spite of his writings being 
punctuated here and there by such words as "possibly," "perhaps," 
"probably," he would seem to have definitely proved that zinc 
chloride should not be used as an obtundent of sensitive dentine, 
because "it is exceedingly dangerous to the life of the pulp," though 
he does not precisely describe what causes this danger, and entirely 
ignores the histo-pathological side of the question. He further 
writes: " In every instance, silver nitrate has proved deeply penetra- 
ting and coagulating with rapidity and certainty very nearly equal 
to zinc chloride;" but still he adds, "The result has not been entirely 
satisfactory." 

• The nearest approach, however, to a scientific attempt to unravel 
these knotty points was that achieved in 1890, by Miller, who, 
nevertheless, limited his observations to the comparative value 
of antiseptics used in dental surgery, making use of pulps which, 
being isolated from the mouth, had lost their natural living surround- 
ings. These, therefore, at present, are unsolved problems, the 
explanations given as to the actual phenomena which occur being 
most vague. 

DIVERGENT OPINIONS ON CERTAIN PROBLEMS 

For instance, Black in his "Operative Dentistry," vol. 1., p. 
193, 1908 in treating of the question of curative effects of fillings 
says: "Fillings cure purely and simply by shutting out everything 

from contact with dentine No systemic change is 

produced as a direct effect." 

Again, Inglis, in the last edition of Burchard's excellent "Dental 
Pathology and Therapeutics," writes: "A process of eburnation 
is set up when the progress of caries is delayed, and in some cases 
ceases." What is the "process of eburnation"? The writer tells 
us: "The continued stimulation of the ends of the dentinal fibrillae 
which are exposed in abrasion causes them either to become 
hypersensitive or stimulates them to formative activity. Tubule 
material is built upon the inner walls of the tubules, obliterating 
their lumen. This is the so-called tubular consolidation or calci- 
fication (eburnation)." 



THE PULP IN CLINICAL DENTAL SURGERY 209 

This statement is in entire disagreement with that of Black, op. 
cit. p. 128, who says: "The suggestion has been made that some 
additions of calcium salts may be made on the walls of the dentinal 
tubules, narrowing their calibre. This is plausible, but as yet no 
sufficient series of measurements have been made to determine 
the facts." And again: "Dentine or enamel once formed is formed 
for all time, it can never be re-formed, changed, or improved in its 
character or qualities." 

By certain clinical aspects of dental surgery, of which mention 
was made just now, is meant the palliative and operative treatment 
of diseases of the pulp. This tissue with an infinite variety of 
disease — inflammation and its terminations, degenerations, senile 
changes, and more remarkable reconstructive potentialities, offers 
but few opportunities to the dental surgeon for the display of his 
surgical knowledge and principles and his skill. They may be 
summarised as two only, the problem being "to cap or not to cap," 
to devitalise or not to devitalise. 

THE QUESTION OF CAPPING EXPOSURES 

A superficial or deep ulceration or incised or punctured wound 
cannot be treated; it is difficult to get rid of an infected condition, 
or restore a functionless pulp to its normal activity, without the 
complete destruction of the organ. The anatomical peculiarities 
of the hard and soft parts are antagonistic to these things. If 
the operation of capping an exposure of the pulp, under the very 
strictest aseptic precautions is successful, it is probably because 
only non-liquefying micro-organisms exist in the dentine and in 
the immediate neighbourhood of the tooth which is being treated. 

In this connection it may be recalled that Goadby {Mycology 
of the Mouth, 1903) has discovered only the Streptococcus pyogenes 
(viridans) and the Bacillus necrodentalis, which are liquefying 
organisms, in the deep layers of carious dentine. 

In 1900, in Paris, the author (Trans. Third International Dental 
Congress) ventured to emphasise the fact that capping was, as a rou- 
tine method of practice, always a failure. It seems to him, after a 
riper experience, that generally the operation is not a success on 
account of the prevalence and presence of these facultative (obli- 
gatory) aerobes, which, according to Goadby, are capable of ob- 
taining oxygen from gelatine, which is the end-product of collagen. 



2IO 



THE DENTAL TISSUES 



THE PHYSIOLOGICAL RESISTANCE OF THE HEALTHY PULP 

But this is not all. There is another factor which is probably 
of greater importance than the presence of these micro-organisms; 
this is the physiological resistance of the pulp. It would seem that 
when the operation of capping is unattended by pain or by death of 
the pulp — no matter how long delayed after the actual treatment — 



p D 




Fig. 198. — Logitudinal section of canine with pulp in situ. Enamel was 
hypoplasic, and subsequently, with the dentine, became carious. There are 
no micro-organisms in the adventitious dentine, p.d. Primary dentine; p. Pulp; 
a.d. Adventitious dentine. Magnified 12 times. 

it is due to the physiological resistance not only on the part of the 
pulp itself, but also on the part of the adventitious dentine which 
has been deposited on its surface. The author has failed in his at- 
tempts to stain bacteria in the pulp and adventitious dentine in some 
carious teeth which presented a hypoplasic condition of the enamel. 
This leads him to suppose that if this adventitious dentine is produced 
early by an energetic pulp, and if the caries proceeds at a slow 



THE PULP IN CLINICAL DENTAL SURGERY 



211 



uniform rate, the pulp will not become infected and the case would 
be suitable for capping an exposure, if one should by any chance 
be made, either idiopathically or traumatically or pathologically. 

Miller considered that there is in the thin free_ margin of enamel 
a certain amount of physiological resistance, as also in the trans- 
lucent zone of carious dentine. 

It is probable, nay certain, that a large amount of physiological 
resistance resides in the pulp also, as witness the unvarying fre- 
quency with which it lays down adventitious dentine. And if a 



PD 



V 



>».' 



.*, 



<.mw 






%■•■■■ •:/m l?->jt!:v ^ 

Fig. 199. — Areolar adventitious dentine — a most suitable nidus for the growth 
and development of the micro-organisms of caries. Rapidly formed as a pro- 
tection of the pulp. p.d. Primary dentine. Magnified 200 times. 

perfect capping has been performed and facultative micro-organisms 
are absent or few in number, and the pulp always retains its high 
degree of physiological resistance, the results will be entirely 
satisfactory. 

Therefore, given a healthy pulp, the success of this operation 
would appear to depend on three conditions: (i) A slight injury, 
(ii) Absence of facultative aerobes, (iii) Well-maintained physio- 
logical resistance of the pulp, and of its adventitious dentine. 

Conversely, therefore, anything which destroys, or reduces, or 
abolishes this physiological reaction, such as prolonged mental 
anxiety, chronic wasting diseases, often repeated traumatisms of 
the hard parts, frequent and varied thermal stimulations, will in 



212 



THE DENTAL TISSUES 



the end, in spite of the aseptic care of the operator, tend to bring 
about disaster, and the pulp will die. 



REGIONAL HYPEREMIA 



Dental caries, when acute, is accompanied in its early stages 
by a regional hyperemia which according to the part attacked — 
that is, that which is nearest to the breach of surface — is either 
coronal, cornual, cervical, or radicular. Sections of teeth extracted 




Fig. 200. — Longitudinal section through a cusp of a molar showing signs ot 
"arrested" caries. Surface of enamel and dentine (where exposed) blackish 
in color, e. Enamel; d. Dentine; c. Caries making breach of surface of enamel 
prior or subsequent to the general arrest of the process. "White spot " absent; 
enamel tissue fully stained. Magnified 45 times. 

during a paroxysm of odontalgia reveal this quite clearly, but 
chronic caries does not necessarily produce it. Coronal regional 
hyperaemia mav exist to a slight degree in such caries, but when the 
physiological resistance of the pulp is fully restored and permanently 
established, not only does this hyperaemia undergo resolution, but 



THE PULP IN CLINICAL DENTAL SURGERY 213 

the contents of the dentinal tubes claim their share in the physio- 
logical resistance, and arrested caries results, often the whole phe- 
nomena of decay and arrest proceeding without any pain. 

ARRESTED CARIES 

One would have thought that arrested caries would have been 
associated with deposits of secondary and adventitious dentine on 
the pulp surface. This is not necessarily so. Specimens of true ar- 
rested caries are not easy to obtain, but those that have been pre- 
pared show no sign of this, nor pathological conditions of the pulp. 
If specimens have been prepared by the Koch-Weil method, even 
before immersion in the graduated alcoholic solutions, the dentine 
is extremely hard and resistant to a fine saw, such as an American 
No. 4. What enamel remains on the surface is also exceedingly 
dense and difficult to cut. Curiously enough, however, and for 
what reason it is at present impossible to determine, the enamel 
rods become stained throughout their length by means of the Gre- 
nadier's borax carmine which is used in conjunction with this proc- 
ess (Fig. 200). The transverse striae are more marked than natu- 
ral, and the tissue has the appearance of having been washed in 
a weak acid solution. This staining of the enamel may not occur 
universally; the calcification of the teeth varies considerably even 
in the same mouth. Still it is evident that but little clinical sig- 
nificance can lie in this fact, although it is interesting from the his- 
tological point of view. 

SOME SENILE CHANGES 

As age advances, the pulp cavity is not encroached upon to any 
appreciable extent by new deposits of dentine as a normal event. 
The author's observations do not accord with Tomes, who remarks 
in the 1906 edition of "A System of Dental Surgery," page 416, 
"The area of the pulp cavity becomes gradually diminished by the 
slow addition of dentine to that which was formed when the tooth 
was in a state of active growth;" nor with those of Dr. Loos, who, 
mScheJf's Handbuch fiir Zahnheilkunde, 1908, states that " There must 
be mentioned a general, physiological, senile new formation of den- 
tine," and continues: "With the entire development of the teeth, nor- 
mal dentine formation does not stop, but continues slowly up to the 
greatest period of age. A proof of this is the fact that the pulp 



214 



THE DENTAL TISSUES 



cavity in advanced age is found to be smaller than in earlier years — 
indeed, it may entirely disappear and this physiological new for- 
mation of dentine produces most diffuse uniform thickening of the 
dentine wall. It appears, however, that this dentine formation does 
not take place uniformly over the whole wall of the pulp cavity. 
The root-canals in advanced age are mostly found narrowed; but 
frequently on the wall of the pulp chamber only certain places are 
distinctly altered, viz. : those which border on the pulp chamber in a 
vertical direction. As the size and form of the pulp cavity are sub- 



A D 




P D 



Fig. 201. — Longitudinal section (mesio-distal diameter) of lower incisor of 
patient aged seventy-one. Pulp chamber filled with debris and detritus by 
grinding. Small amount of adventitious dentine — marked attrition. p.D. 
Primary dentine; AD. Adventitious dentine. Magnified 12 times. 



ject to manifold individual variations, it is often very difficult to 
find out whether we have to do with normal or with altered condi- 
tions. Histologically this dentine does not exhibit any noteworthy 
differences from the normal, and it can scarcely be distinguished from 
substituted dentine or 'odontheles' (pulp nodules)." 

If this is a normal physiological process on the part of the pulp, 
one would expect to find it universally in all senile teeth; but it is 
not so. The accompanying figure for instance, is a case in point, 
where the diameter of the pulp chamber measures 3 mm. (Fig. 201). 
The history of the tooth was as follows: "Male, aged seventy-one. 



THE PULP IN CLINICAL DENTAL SURGERY 



215 



No inflammation of pulp, slight amount of tartar, tooth loose, not 
isolated in position, alveolar process absorbed and walls of sockets 
thinned, 'pyorrhea' present very markedly." 

It is quite impossible to understand how calcification of the 
dentinal tubules can occur and how the pulp chamber can become 
lessened in size, except by the production of new adventitious den- 
tine. Of course odontoblasts are still present up to the end of the 




Fig. 202. — Longitudinal section of a senile tooth, e. Enamel; p.d. Primary 
dentine, c.p. Calcified pulp. Magnified 12 times. 



life of the pulp, but they are not functional after the fiftieth or 
sixtieth year. When the process of dentinification has ceased, and 
fresh secondary dentine is deposited, the microscope usually exhibits 
very clearly the line of demarcation between young and old tissue. 
The idea which has been current for generations probably arose in 
the attempt to account for the discrepancies in the size of the 
calibre of the dentinal tubules at their centripetal and centrifugal 
extremities. 



2l6 THE DENTAL TISSUES 



SYSTEMATIC DENTAL HISTORIES 



At this juncture the writer must digress slightly from his subject 
in order to draw attention to the need for and the methods of system- 
atically obtaining reports of teeth which should be of scientific 
value when research work is being done. He refers to the individual 
''histories" of teeth. It is important that the investigator should 
learn thoroughly all he can about the objects he studies, and so it 
seems imperative that with regard to teeth which are about to be 
examined the following points should be ascertained: (i) Age of 
the patient. (2) Sex. (3) Denomination of the tooth. (4) Ob- 
vious disease of the pulp or periodontal membrane. (5) Presence 
of "pyorrhea alveolaris." (6) Position of the tooth or teeth in 
regard to the dental arch. (7) Conditions of the socket at the time 
of extraction. (8) Presence or absence of tartar. (9) Presence or 
absence of any obvious lesions of the hard parts, such as attrition, 
abrasion, or erosion. 

The Age of the patient is useful as a general guide as to what to 
expect. One need not dwell on the importance of this in the young. 
Apart from the question of age in treating the irregularities in 
position of the teeth, it is equally essential to ascertain the age of 
the patient in order to gage somewhat the conditions of the pulp or 
root membrane. Thus one knows that the apical foramen in the 
permanent canine is closed shortly after the tooth has erupted. 1 One 
knows that the pulps of elderly people become less sensitive as years 
pass by. One knows that there are three cornua to the pulp of the 
permanent first incisor up to the fifteenth year, when they disappear; 
and so on. But age does not always prove a reliable guide, for, as 
has been already shown, very frequently the pulps of children's 
deciduous and permanent teeth may exhibit senile and other de- 
generative changes. 

Sex. — One cannot recognize with facility the difference, either 
macroscopically or microscopically, between the teeth of a male or 
a female patient. Of course this degree of variation is nothing like 

1 The approximate dates of "closure" of the apical foramina of the permanent 
teeth may be given as follows: A. The Maxillary series — First incisor, nth year; 
Second incisor, nth year; Canine, 13th year; First premolar, 12th year; 
Second premolar, 12th year; First molar. 12th year; Second molar, 15th year; 
Third molar, 19th year. B. The Mandibular series — First incisor, 10th year; 
Second incisor, nth year; Canine, 13th year; First premolar, 12th year; Second 
premolar, 12th year; First molar, nth year; Second molar, 16th year; Third 
molar, 21st year. 



THE PULP IN CLINICAL DENTAL SURGERY 217 

so great as between the hair, or brain, etc., of the two sexes. The 
curvatures of the enamel rods are apparently the same; the structure 
of the two pulps is apparently identical. But the author believes 
that there is a dissimilarity between them in the size, the structure, 
and the chemical and functional characteristics of the teeth. 

Regarding the first, Amoedo (L'Art Dentaire en Medecin Legale, 
1898) records in a tabulated form some measurements made by 
Mela between the size in transverse diameter of the first and second 
incisors of man and woman. The figures show that the mean dif- 
ference between the dimensions in a mesio-distal direction of the 
first maxillary incisors of the two sexes is 0.627 mm.; of the maxil- 
lary second incisors 0.159 mm. The mean measurements between 
the maximum diameters of the first and second incisors was 2.25 
mm. in man, and 1.89 mm. in woman, a difference of 0.38 mm. The 
maximum diameter of man's first incisors gave a maximum of n mm. 
and a minimum of 7.5 mm., that of the same teeth of woman giving 
a maximum of 9.8 mm. and a minimum of 7.1 mm. "La difference 
sexuelle entre les deux extremes des incisives centrales superieures," 
he writes, "est de 1.3 mm. a. l'avantage du sexe masculin. . . 
La difference sexuelle entre les deux extremes des incisives laterales 
superieures est de 5 mm. en faveur du sexe masculin." 

Regarding the last, the teeth of women would appear to be less 
subject to attrition or abrasion; they cannot be influenced by the 
same amount of muscular power as the former, though the food is 
more or less identical. The respective dental and muscular dynamics 
and potentialities of mastication are distinct, and if tested by means 
of a dynamometer would probably be found to differ. 

Comparative anatomy teaches that the teeth of the female vary 
in development, in size, and sometimes in function, from those of 
the male; instances need not be given. We also learn that if but a 
slight amount of work has to be accomplished, tooth structure is 
profoundly modified. Thus the Edentata have no enamel, simply 
because their food is of so soft a character as to involve practically 
the abolition of the function of mastication. Again, the enamel of 
the Manatee is arranged in rods which run straight courses; on the 
other hand, that of the rodents, particularly the beaver,' presents a 
most complicated pattern. The former does not require for eating 
aquatic plants a dense structure such as the latter, whose teeth are 
used for gnawing and chiseling the barks and trunks of trees. Hence, 
at first sight, though it seems strange to suppose this x difference 
between male and female teeth, there is some support for the idea. 



2l8 THE DENTAL TISSUES 

At all events, the author thinks that there is certainly some ground 
for the belief that the pulps of the teeth of women may and often 
do undergo unique vascular disturbances at certain periods of their 
lives; and this fact alone would constitute a fundamental difference 
between the two. 

The Denomination of the tooth is important. The enamel of 
incisors is less complex in pattern than that of the molars. From the 
chemical point of view, also, there is a remarkable difference. Gass- 
mann, in the Zeitschrijt fur Physiologische Chemie, 1908, discovered 
as a result of his investigations that human canines contain 29.78 
per cent, of calcium salts, third molars 31.65; of water combined 
with the organic matters, 8.09 in the former and 6.91 in the latter. 
Pulps appear to be histologically identical, but most probably there 
is here again a dissimilarity which one is not clever enough at present 
to detect and acknowledge. 

In other words, just as there are no two persons exactly alike, 
no two animals, no two birds, no two plants, no two blades of grass, 
so there are no two teeth precisely and in every minute particular the 
same. 

With regard to the other points which have been outlined, which 
should be given in the histories of cases, one need not dwell on each 
in detail. One will merely add that a tooth which is isolated in 
position, from removal of anterior and posterior neighbours, is more 
likely to undergo morbid changes than one which is part of an un- 
broken series, owing to the undue strain or shock of mastication; 
that a loose tooth is a degenerate or degenerating organ, and that the 
presence or absence of calculus is of great importance, inasmuch as 
the greater the amount of tartar which incrusts the surfaces, and the 
longer it remains in situ, the less functional the tooth and therefore 
the more liable to become impaired the pulp. 

In addition to this, the naked-eye examination of the specimen 
must be described, viz. : the amount of tartar (if present); its position 
on the root or roots; its distance from the cervical margin; its nature; 
the translucence or otherwise of the apical region of the root; the 
deflections or normal appearances of the root; the amount of abrasion 
of the crown, etc.; in short, all the abnormal characteristics of the 
object under consideration as far as the macroscopical appearances 
are concerned. 



THE PULP IN CLINICAL DENTAL SURGERY 



219 



(II.) Non-Carious Lesions 

(a) LESIONS DUE TO TACTILE, THERMAL, CHEMICAL, AND 
ELECTRICAL STIMULATIONS 

(1) Tactile impressions which set up pain are, as is well known, 
those in relationship with the surfaces of the cervical margins of the 
teeth. No lesion mav exist to the naked eve; but there is a micro- 




Fig. 203. — Cementum, showing its hyaline character and absence of lacuna?, 
the three dark masses being foreign bodies on the surface of the tissue, d. 
Dentine; c. Cementum; p.m. Periodontal membrane; a. p. Alveolar process. 
Magnified 250 times. 

scopical one. These hypersensitive surfaces very frequently, indeed, 
develop into acutely esthetic cavities. Whence comes the pain? and 
what is found on histological examination? A tiny strip of dentine 
uncovered by the other hard tissues. The anatomical relation- 
ships of the hard tissues at the necks of teeth are as follow: (a) 
Enamel overlaps the cementum in about .5 per cent, of cases. (J) 
Cementum overlaps the enamel in 60 to 65 per cent, of cases, (c) The 



220 THE DENTAL TISSUES 

two tissues meet bout a bout in 30 per cent, of cases, (d) Finally, 
they fail to meet at all, and leave the peripheral surface of the dentine 
exposed, in 5 to 10 per cent, of cases. 

Thus normally, it would appear, that the two tissues are in 
absolute contact, and both lie in the same plane without any 
involution whatever (see Chap. Ill, Vol. 1). 

Now, enamel being outside the pale of nutrition, and once formed 
always formed, and cementum itself being insensitive, it is clear 
that the dentinal tubules are actually exposed at their distal ex- 
tremities, and their contents are irritated by the pressure or presence 
or friction of a foreign body in that region. Enamel is nerveless, 
and cementum in normal conditions does not contain any elements 
of a nervous or protoplasmic character in sufficient amount to induce 
pain in suitable circumstances. No doubt prolonged irritation 
might lead to exalted sensibility on the part of the pulp, and if 
decalcification of the thin edges of the enamel and cementum takes 
place, with loss of substance, an erosion cavity is produced. 

(2) Thermal sensations are easily explained, owing to their being 
due to a raised or lowered temperature of the pulp through conduc- 
tion on the part of the enamel — a state of things which the pulp 
immediately recognizes, by means of the dentinal fibrils. It does 
not always happen that a pulp is painful when icy-cold or hot water 
is placed on the enamel. When it is, however, it is either hyperaes- 
thetic, or perhaps more correctly, hyperalgesic, and is more readily 
affected by outside influences than it should be, or the sensorium 
is more appreciative than natural of the impressions conveyed to 
it from the pulp. 

Occasion arises sometimes when a devitalised tooth whose pulp 
has been removed gives the impression to the patient by pain that 
it is still present and alive. The exhaustion of air around the neck of 
the tooth — that is, an alteration in or lowering of the local tempera- 
ture on the part of the patient — gives rise to pain. On examination 
it may be found that the interdental gum may have been inadver- 
tently removed while operating on the adjacent tissues, and the 
free edge of the periodontal membrane nearly exposed. It is there- 
fore probable that the root membrane transmits the sensations of 
pain to the brain, which interprets it as that coming from the pulp. 
With regard to those cases of a root or portion of a root which, having 
been denuded of its alveolar socket and mucous membrane, such as 
is frequently observed in connection with the palatal roots of 
maxillary molars, is very sensitive to thermal changes, and is 



THE PULP IN CLINICAL DENTAL SURGERY 



221 



rendered insensitive by means of the application of silver nitrate, the 
author is not prepared to state what really occurs. Cementum is 
incapable per se of transmitting sensations; and "the living chain of 
protoplasm" which Bodecker so deftly described as passing from the 
dentinal fibrils through the granular layer of Tomes to the lacuna? 
and canaliculi of the cementum, and so on to the nervous bundles of 
the periosteum, is a myth. For a solution of silver nitrate cannot 




Fig. 204. — Same as preceding, but differently illuminated, to show granular 

character of cementum. 



soak through cementum whose free layers are almost homogeneous 
in character and hyaline in structure (Figs. 203 and 204). 

If a pulp is frequently painful when hot substances and fluids are 
taken into the mouth, it indicates that, though there may be no 
apparent lesion, it is certainly on the "down grade." 

(3) Chemical Stimuli.- — The application of lukewarm mineral acids 
or alkalis to an unbroken surface of the teeth gives rise to no pain in 
the pulp. 

(4) Electrical impulses, however, are full of interest. "Electric 



222 THE DENTAL TISSUES 

cells are frequently formed in the mouth, metallic poles being present 
and an electrolyte intervening. The greater the electro-positive 
or electro-negative the metal, the greater the electro-motive force. 
Now, in the electrolytic scale, gold is nearly the most electro-negative 
of all metals placed in the mouth ; while aluminium is the most electro- 
positive. If, therefore, two metals of different electromotive force 
come into contact or almost into contact, and the saliva is ionized 
to such an extent as to be efficiently electrolytic, the cathions, or — 
ions, will move toward the + pole or more electropositive side, while 
the anions, or + ions, will move toward the — pole, and a certain 
amount of electricity will be evolved. 

" This action maybe carried to a greater degree than is usual in the 
mouth. Clinically this force becomes more manifested, at times, 
under certain conditions, in a disastrous manner. Thus a 16-carat 
gold band which is used for supporting a denture, if attached to a 
molar tooth, for instance, which contains a large amalgam filling, 
may in these cases become so electrically affected as to break, on 
account of. the molecular changes set up by the current, and the 
filling similarly to become disintegrated and fall out. 

" Mere contact of a metal with enamel or dentine is not appreciated 
by the pulp. It is when two dissimilar metals are brought into 
contact, separated only by a thin film of saliva, which acts as the 
electrolyte, and the circuit is completed, that voltaic currents are 
set up — as for instance when the metal ring of a small mirror touches 
the surface of a gold or an amalgam filling. This, of course, con- 
stantly takes place during operations, and is as a rule unnoticed by 
the patient, on account of its extremely light character; but at times 
the pulp, stimulated by the electrical action, responds by a sudden 
spasm of acute odontalgic pain." ("An Introduction to Dental 
Anatomy and Physiology" 1913.) Is the pulp normal in these latter 
fairly rare cases? Probably not — it is beginning to undergo morbid 
changes; for the phenomenon may be observed, as far as clinical 
experience goes, equally beneath large as well as less bulky fillings. 
The pulp is not hyperaemic; it is hypersensitive, or particularly 
" receptive," — owing, no doubt, to an exalted condition of the cerebro- 
spinal nervous system which happens to be synchronous with the 
electrical phenomena. Tests as to the acidity or otherwise of the 
saliva are unattended by success. Here, of course, mere contact 
with the filling alone induces no response; the circuit must be com- 
pleted, either by simultaneously touching filling and tongue or 
filling and buccal mucous membrane. 



THE PULP IN CLINICAL DENTAL SURGERY 223 

It is interesting to note that the same degree or kind of reaction of 
the saliva may not obtain simultaneously in the same mouth. Thus 
some portions of the gums or buccal mucous membrane may show, at 
the same moment, an acid, an alkaline, and a neutral reaction to 
litmus paper. 

(b) REFERRED PAIN AND OBSCURE REFLEX ACTS 

Entirely different from these local manifestations are those nerve 
pains set up in apparently sound teeth on holding lukewarm saccha- 
rine substances in the mouth. 

A particularly sweet body, for instance, will at times, when the 
functions of the central nervous mechanism are exalted, give rise to 
intensely acute pain which may last an appreciable length of time 
and then passes slowly away. This is no mere gustatory hallucina- 
tion, no co-ordinated association of ideas, but a physiological fact. 
Here is a reflex act. It is impossible for sugary solutions per se to 
so rapidly attack enamel or cementum or even exposed dentine as 
to induce these pains. The length of time required for the paroxysm 
to make itself felt after the application of the stimulus is about 0.05 
to 0.06 of a second. It is not through the hard tissues that the im- 
pulse passes, it is through the nerve supply of the pulp. The 
afferent nerves are those sensory branches of the Fifth which supply 
the oral mucous membrane, and the gustatory and glossopharyn- 
geal, with possibly the Chorda tympani; and it is the act of placing 
the saccharine-bearing material on the tongue and inside of the cheek 
that brings about the reflex act. This, too, only occurs at times, 
when probably the sensorium is especially liable to receive and trans- 
mit slight impulses to teeth, the pulps of which, while not degenerated 
are certainly not entirely normal. 

There are many examples of the pulps of teeth causing pain when 
there is no obvious lesion. Occasionally the eating of very sweet 
or sour bodies will set up excruciating synalgia in sound teeth. 
Through the glosso-pharyngeal and the Chorda tympani nerve sen- 
sations are felt by the brain, which as in the case of the amputated 
foot makes an error of judgment as to the position of the stimulus. 
In its essence it is akin to mysophobia and certain other systemic 
morbid emotivities. 

Reverting for a moment to this question as an aid to the proper 
understanding of this reflex act, we know that mysophobia, or the 
fear of improper or inapposite contacts is not confined to manifes- 



224 THE DENTAL TISSUES 

tations in the form of a natural aversion to touching disagreeable 
bodies, or those capable of undergoing decomposition. Many people 
cannot bear to perceive, by the sense of touch, the surface of fab- 
rics such as velvets or silks, or the external parts of the skins of 
fruits such as peaches. There may arise in the minds of some, 
fear of contact with metallic objects, such as copper, pins, and nee- 
dles, or, according to Morselli, pieces of glass. It is possible that 
derangements of the tactile digital sensibility are partly the cause; for 
Marce has described a case in which, through a fear of seeing pins 
or needles adhering to the fingers, complete insensibility of the skin 
of the hand was produced. Among other illustrations of systemic 
morbid emotivity, Morel, quoted by Dr. Charles Fere in his "La 
Pathologie des Emotions," 1899, cites the following: King James 
II of England trembled at the sight of a naked sword; Erasmus 
suffered from febrile fits on seeing a plate of lentils; Scaliger was 
seized with nervous tremors at the sight of a carafe of water; Bacon 
experienced the state of syncope during every lunar eclipse. 

"setting the teeth on edge" 

The complex series of phenomena constituting that anomaly of 
sensibility popularly spoken of as "setting the teeth on edge" 
may perhaps be placed in the same category as the preceding 
illustrations, for, in this case, it is partly the outcome of an innate 
antipathy on the part of the individual. It is something more than 
a mere reflex act, inasmuch as it is accompanied and complicated 
by a mentality which is the effect of the workings of a higher con- 
scious cerebration. This syncinesia, among others studied by John 
Hunter, Miiller, and Gubler, which is purely physiological, or perhaps 
borders on the abnormal, may be caused partly by the action of 
the auditory nerves, and partly by the gumaisthenic or somaisthenic 
perceptions of the person. 

Gumaisthenic Perceptions. — The phenomenon was known to the 
Prophets of old whose words, recorded in the Bible, are as follow: 

Prov. x, 26: As vinegar to the teeth, and as smoke to the eyes, so is the 
sluggard to them that send him. 

Ezek. xviii, 2: What mean ye, that ye use this proverb concerning the land 
of Israel, saying "The fathers have eaten sour grapes, and the children's 
teeth are set on edge ?" 

Jer. xxxi, 29, 30: In those days they shall say no more, The fathers have 
eaten a sour grape, and the children's teeth are set on edge. But every one 
shall die for his own iniquity: every man that eateth the sour grape, his 
teeth shall be set on edge. 



THE PULP IN CLINICAL DENTAL SURGERY 225 

Ousaisthenic Ideas. — Shakespeare declared: 

I had rather hear a brazen canstick turned, 
Or a dry wheel grate on the axle-tree; 
And that would set my teeth nothing on edge, 
Nothing so much as mincing poetry. 

— 1 Henry I V, iii, 1. 

Through the action of the auditory nerves the grating of a dry- 
wheel or stick of schoolboy's pencil on his slate may induce it; and 
not infrequently the tactile sense. When the fingers are rubbed 
lightly on the surface of a piece of velvet, this curious sensation of 
pain in the teeth is noticed. Somaisthenic ideas become converted 
into a modified form of acute odontalgia. If the fingers are rubbed 
on a piece of glass-paper or a hot metallic surface, the mind appre- 
ciates the condition thus induced locally, and pain is felt, not in the 
teeth, but in the digital extremities themselves. 

The explanation of the conversion of the somaisthenic percep- 
tions into pain would seem to be the following: 

The simple act of touching the velvet does not per se induce pain, 
and would not do so if the mental attitude of the individual were not 
an anticipatory one. He has the knowledge that his teeth will 
ache, and that possibly a cold tremor will pass down his spine, as 
his fingers are brought into contact with the velvety field. It may 
be that the brain is unaccustomed to determine the amount of mus- 
cular effort set up by the digital movements, or that it is disturbed 
by the unusual and somewhat naturally repellant act. There is 
no doubt that there is a great limitation to the capacity of the syn- 
thetic action of our minds in appreciating the changes which occur 
within our bodies, and the mechanism of the brain frequently fails 
in its estimation and correct interpretation of what is going on. 

Other kinds of obscure reflexes, not due to pathological causes, 
may be cited. Pressure on the supraorbital branch of the frontal 
division of the ophthalmic nerve may induce pain in a maxillary 
canine. An observer tells the author that when, in India, he has 
witnessed children sucking sticks of sugar-cane, he himself has had 
toothache. 

So it is obvious that the optic, the auditory, and more than 
all, the trigeminal nerves, are closely associated with these reflex acts 
in health as well as in disease, and that as diseases of the teeth, 
caries and the like, will produce reflex disturbances in the organs and 
parts supplied by them, so they, conversely, under certain forms of 
irritability will set up odontalgia. 



226 THE DENTAL TISSUES 

RECEPTIVITY OF THE PULP: ITS HYPERESTHESIA AND 
DYSESTHESIA 

But ordinarily no pain is felt; when it is, however, the condition of 
the pulp is that of dysesthesia, and comes on only when the central 
and peripheral nervous systems are in a state of excitability or 
receptivity. 

The physician is often brought face to face with other varieties of 
hyperaesthesia, such as gastralgia, enteralgia, the epileptic aura, and 
so on. And the term dysassthesia is used in connection with the organs 
of special sense, and the condition indicated by the appearance of 
subjective phenomena referable to these organs — "of the eye, 
by the appearance of sparks and flames; of the ear, by the perception 
of sounds, such as humming or buzzing; of the nose, by the percep- 
tion of odors; of the tongue, by the perception of flavors" (Bris- 
towe), and finally, of the teeth, by the recognition of those interest- 
ing reflexes to which allusion has been made. 

(c) DISTURBANCES OF THE VASCULAR SYSTEM IN THE PULP 

Allied to these morbid states, but totally different in origin, 
are those other conditions a few particulars of which may be now 
mentioned. 

Odontalgia of a severe type may be induced by morbid conditions 
of the blood, which circulating through the vessels of the pulp 
produces pain and organic change in that tissue. 

Increased intradental blood pressure. To Dr. Ferdinand Tanzer 
{Oesterr-ung. Yicrteljahrsschrift f. Zahnheilkunde, 1907) belongs the 
credit of first drawing attention to the effects of increased blood 
pressure in the pulp. If a pulp is very small, as the result of ana- 
tomical overgrowth or developmental defects of the hard parts, 
or is habitually amemic as a result of systemic disturbances, any 
rise of blood pressure in it may induce pain. It is first dysssthetic, 
then hyperassthetic, and then hyperaemic, and lesions of the vascular 
system may follow, leading ultimately, if long continued, to fibroid 
degeneration, death, and gangrene. 

The causes of these obscure forms of odontalgia may be divided 
into (i) congenital and (ii) acquired. 

The former are associated with puberty and the catamenia. 
The signs and symptoms are as follow: Severe pain in apparently 
normal teeth, generally occurring in girls and women, which are 



THE PULP IN CLINICAL DENTAL SURGERY 



227 



agonizing in character and practically resistant to dental thera- 
peutics. There is no obvious lesion. 

If a tooth is removed and examined microscopically it may happen 
that a marked congenital defect can be noticed. If the pulp is too 
small for the tooth — if the area of the pulp is diminutive and that 
of the hard parts unduly large, indicating that enamel and dentine 
have been produced at the expense of the soft tissues (as in Fig. 




Fig. 205. — Longitudinal section of molar showing small size of pulp and great 
thickness of hard parts. (History of tooth narrated in text.) d. Dentine; p. 
Pulp; c. Cementum. Magnified 12 times. 



205) — the increased blood supply would probably be attended by 
pain, partly because the small size of the pulp reduces its trophic in- 
fluences on the tooth itself, partly because of the hydrostatic conges- 
tion that has taken place, partly because of the absence of a collat- 
eral circulation, and partly because the character of the chemical 
constituents of the blood is altered at these periods. 

Thus, it has been proposed by Dr. Blair Bell, Proceedings Royal 



2 28 THE DENTAL TISSUES 

Society of Medicine, 1908 — who claims that the metabolic processes 
concerning the calcium economy exercise an all-important influence 
upon the genital functions and are necessary factors therein — that 
the well-known vaso-dilatation which occurs in the combs and wat- 
tles of laying hens is due to the drop in (i.e. loss of) the calcium 
contents of the blood, whereby a sort of chilblain condition is 
produced. 

If vaso-dilatation or local hyperaemia can occur, as suggested, in 
the peripheral organs of the hen, it is conceivable that a rise of 
blood pressure in the pulp can also be produced in similar circum- 
stances. Such a case, to which allusion has been made, occurred 
in the practice of a friend of the author, to whom he is indebted for 
the following particulars: 

Xotes on a Case of Obscure Odontalgia 

"October 14, 1906. Miss K., aged fourteen. No caries. Pain 
experienced along the upper and lower jaws on the left side. All 
teeth were painful on pressure and slightly loose. Pain in joints. 
Saliva, very acid. Pain more intense during cold or damp weather. 

"Diagnosis: Rheumatism of jaws. 

"The patient was sent to a physician who reported: 'Patient suf- 
fering on October 24, 1906, from slight rheumatism and hyperchlor- 
hydria. The latter was rapidly cured by the administration of 

magnesium peroxide Later on (June 1907), when I saw 

the sections of the patient's teeth, I thought that the trouble might 
be due to deficiency of calcium salts and a lower coagulability of the 
blood. I therefore put her on a course of calcium lactate. I saw 
her three weeks later, when I ordered her to continue the treatment 
for a full six weeks in all, and have not seen her since.' 

"The dental pain gradually departed. 

"May 1, 1907: For four days patient complained of intense pain 
in the left mandibular second molar. Tooth tender on percussion; 
affected by temperature. Local and internal remedies of no avail 
for any length of time. 

"Diagnosis: Presence in pulp of pulp nodules. 

"May 7th: Extracted tooth: Too tender to bur out. Tooth sub- 
mitted to microscopical examination; no pulp nodules on section- 
ising (see Fig. 205). 

"June 7th: Great pain in left mandibular first molar; symptoms as 
before. It was thought the condition might be due to extra blood 



THE PULP IN CLINICAL DENTAL SURGERY 229 

pressure in the pulp. Tried all local and internal remedies as before. 
The only thing that relieves the pain is abstraction of blood by 
leeches, but the effect is only for a few hours. 

"June 20th: Extracted tooth. Sent the patient again to the phy- 
sician to have blood tested. 

"Between last date and March 1908 patient complained of pain, at 
times in the left maxillary second molar, but the physician's treat- 
ment after three doses generally relieved the pain. 




& 



P N 



Fig. 206. — Longitudinal section of premolar of child, p. Pulp; d. Dentine; 
p.N. Pulp nodule. Magnified 12 times. 

March 12, 1908: Great pain experienced in left maxillary second 
molar; insomnia. Applied leeches, with some relief. Found a 
small pinhole cavity, but drilling gave rise to intense pain. Pa- 
tient had an anaesthetic and then the pulp was drilled into. Great 
relief followed, accompanied by much haemorrhage. This having 
ceased, I removed the pulp under cocaine pressure anaesthesia. The 
root-canals were very small. Filled them with light dressing, 
with temporary gutta-percha in cavity. 



23° 



THE DENTAL TISSUES 



"March 19th: Filled root-canals and filled the tooth. 

"June nth: Great pain all night in the tooth. Applied aconite 
and iodine, with no result. Drilled into canals left open, then ap- 
plied a light dressing. 

"June 12th: Pain getting worse; patient up all night; tooth very 
tender. Extracted tooth. Canals were all open; two roots cov- 
ered slightly with glairy exudation, one of them having a slight 
nodule and slight absorption. 





Fig. 207. — Longitudinal section showing fibroid degeneration of pulp in 
deciduous] incisor. D. Dentine; p. Pulp; A. Abraded area of dentine. Magnified 
12 times. 

"The gums were always normal — never injected or tender, except 
in the last instance, when they were slightly tender." 



PHASES OF DEGEXERATIOX 



Acquired lesions are those of the vessel walls induced by such sys- 
temic disturbances as are found in anaemia, chlorosis, gout, maras- 



THE PULP IN CLINICAL DENTAL SURGERY 23 1 

mus, etc. Here more or less permanent injury is done to the coats 
of the arteries and veins, resulting in haemorrhage, thrombosis, 
chronic endarteritis, calcareous degeneration, and so on. 

If calcareous degeneration in the form of pulp nodules (see Fig. 
206) or attached new growth occurs, and is profound, the symptoms 
are similar to those of developmental origin, but the result of the 
treatment is not the same, inasmuch as extraction of the apparently 
sound tooth immediately cures the odontalgia. 

If the former conditions exist there is little if any pain complained 
of. The patients are young children, but the pulps are approaching 
senility, as is evidenced by their exhibiting various phases of re- 
ticular atrophy or fibroid degeneration (see Fig. 207). 

This degeneration is extremely common, and is probably due, as 
a complication, to thrombosis of the capillaries and veins, and as a 
result the impairment of the vaso-motor mechanism, which leads 
to vaso-dilatation and diseases of the vessel walls generally. 

OBSCURE CAUSES OF ODONTALGIA 

Odontalgia may thus occur in teeth unaffected by dental caries. 
It is then due to one of the following causes: — A. Increased or 
diminished blood pressure in the pulp; B. Pulp nodules; C. Adtered 
chemical constituents of the blood; D. Intra-oral electrical im- 
pulses; E. Reflex from the tongue; F. Lesions of Vth nerve; G. 
General neurasthenia and debility. 

In conclusion, these remarks on non-carious and non-apparent 
lesions of the pulp may be epitomized by saying that, as this organ 
is influenced pathologically by general diseases of the nervous and 
vascular systems, obscure cases of odontalgia should always be 
regarded from the standpoint of the physician as well as of the dental 
surgeon; and that, if there is a marked personal or family history of 
gout, rheumatism, or allied conditions, pulp nodules may be diag- 
nosed; if the patient is anaemic, chlorotic, or marantic, or recovering 
from a long febrile disease, early stages of fibrosis may be suspected; 
also that hyperesthesia or dysesthesia is indicated when a patient 
is neurotic, or neurasthenic, or subject to ''nerve storms," or is 
suffering from a form of nervous excitability or exaltation, or per- 
haps exhaustion. 



CHAPTER IX 

THE VASCULAR LESIONS OF THE DENTAL PULP 

Introductory — Anatomical considerations — General effects — Histo-pa- 
thology — Causes — Clinical significance. 

INTRODUCTORY 

Of all the different tissues that go to form the component parts 
of a tooth, the pulp is the most interesting. It is likewise the most 
important, for on its vascular and nervous mechanism depends the 
vitality and therefore the utility of each unit of the masticatory 
apparatus. The strikingly singular character of the anatomical 
distribution of the vascular supply arrests attention, and the 
impartial observer, who might be suddenly called upon to study 
fully and critically the diseases of the pulp as an entirely new field 
for his own exploitation, would probably note that fact at the com- 
mencement of his laboratory experiments and experience. 

ANATOMICAL CONSIDERATIONS 

Two facts stand out pre-eminently as being of great significance — 
(i) the absence of a collateral circulation in the pulp itself, and (2) 
the non-valvular character of the veins, which at the same time are 
non-collapsible. 

(1) With regard to the former, it may be recalled that during the 
development of the teeth the tissues formed from each layer of the 
primitive blastoderm are supplied by two separate groups of vessels, 
of which the internal set, distributed to the mesodermic structures, 
vascularize the dentine papilla, the dental sac, and the surrounding 
bone. In adolescent and adult pulps the branches of the internal 
set enter the apical foramina of the teeth usually as a single trunk, 
which may measure as much as 83/x in width, to become almost 
immediately bifurcated and divided into many subsidiary branches, 
ending near the basal layer of Weil in an anastomosis of capillary 
loops whose individual lumina are roughly, on the average, about 
8/i in diameter (see Chap. VII, Vol I). 

232 



THE VASCULAR LESIONS OF THE DENTAL PULP 233 

If the lumen of the main artery, entering the apical foramen, 
is by any means occluded, the integrity of the whole of the vascular 
system is imperilled, as there are no collateral branches to restore 
the balance in the blood-stream. This actual condition is almost 
if not quite unique in the general anatomy of the body. 

These remarks apply with no element of uncertainty to the 
vascular system of the single-rooted teeth. It cannot, however, 
be asserted with equal confidence that the pulps of molars have no 
collateral circulation. The exact method of distribution in these 
larger teeth has never been ascertained, owing to the difficulties 
encompassing the performance of an artificial injection of the vessels 
in adult age. But clinically it would seem to be impossible for a 
collateral anastomosis to exist; and from an embryological point of 
view the statement of Lepkowski may most probably be relied 
upon. This observer shows (Anatomise her Hefte, 1901) that "In 
the germ of the two-cusped tooth there are present two bundles 
of vessels separated from one another," etc. (see Chap. XII, Vol. I). 

(2) Again, on account of the patency and non-valvular character 
of the veins it may be assumed that exogenetic influences in normal 
circumstances cannot affect the flow of blood in the pulp. The veins 
are not subjected to muscular or other external pressure, and in 
this respect agree with other similarly constructed tubes, such as the 
superior and inferior vena cava, the pulmonary veins, and those in 
the interior of the cranium and vertebral column, and long and 
short bones. 

Hence it is observed that these two facts are conspicuously 
apparent, the first being probably of the greater importance, as the 
general systemic veins that are 2 mm. and less in diameter are un- 
provided with valves. But the significance of the absence of a 
collateral circulation on the causation of diseases of the pulp cannot 
be overestimated by the perspicacious and discriminating student. 

GENERAL EFFECTS 

After due consideration of these anatomical conditions it is not a 
matter for surprise that lesions or degenerations arising from varia- 
tions in the blood current or in the blood pressure in the dental pulp 
should be fairly common. So much is this the case that one would 
probably be not far from the truth in asserting that, while teeth are 
so very frequently the victims of dental caries, they may also 
equally and simultaneously be subjected to internal retrogressive 



234 



THE DENTAL TISSUES 




Fig. 208. — Longitudinal coronal section of premolar with pulp in situ, showing 
thrombosis of capillaries and other vascular lesions. Prepared by the Author's 
process; stained with Ehrlich's acid haematoxylene. A. Branch of main artery; 
v. Enlarged vein; c. Capillary filled with thrombus; T. Thrombus becoming 
organised; f. Early stage of fibrification of pulp tissue proper; o. Odontoblast 
layer increased in width and in the number of its cells. Magnified 45 times. 



THE VASCULAR LESIONS OF THE DENTAL PULP 235 

changes induced by a lowered or altered physiological resistance 
on the part of the pulp, through the unusual characteristics of its 
blood supply. This does not apply entirely to the normal individual, 
but more especially to those persons who suffer from disturbances of 
the circulatory system. 

It is well known that many persons undergo a certain temporary 
discomfort brought about by hypersemia of the pulp. For some 
reason or other the vessels become vicariously over-filled and undergo 
hydrostatic congestion, which presently disappears when the cause 
is removed or when there is a good outlet provided for a free flow. 
If, however, the intradental pressure is so severe as to prevent the 
occurrence of an efficient and quick relief, then the tissues degenerate 
and perhaps die, as they are unable, on account of their dentinal 
environment, to accommodate themselves to their engorged state. 

Tanzer (see Chapter VIII) records a case — among others — where, 
on account of the circulatory irregularities in the internal genital 
organs and adnexa of a patient, the pulp of a tooth died as the result 
of the abnormally increased intradental blood pressure. The 
introduction of metal fillings and cement floorings into carious 
cavities is sometimes followed ultimately by local pain, and the 
work of obturation is credited by the uninformed with being the 
cause of the odontalgia, while it is merely often due to either 
reflex nervous irritation or a rise in the local blood pressure. The 
writer just quoted proceeds to summarise his remarks by saying 
that this increased intradental blood pressure may arise as a con- 
sequence of diseases due to circulatory deflections from the normal, to 
conditions of high nervous tension as in hysteria, to influenza, 
pregnancy, or occasionally as the result of traumatism. 

It is thus clear that temporary engorgement of the vessels in 
the pulp tends to produce odontalgia of varying degrees of severity; 
but if this congestion be continued it leads eventually to death of 
the parts and cessation of pain. This may be brought about (a) 
slowly, when the tissues pass through the various stages of fibroid 
degeneration, or (b) rapidly, when moist gangrene supervenes as a 
result of thrombosis, and arterio-sclerosis and sudden death en 
masse takes place. 

It is believed that slight rise of blood pressure produces no 
symptoms of neuralgia, though it can be readily conceded that 
nerve pain from other areas may be reflected to a tooth which is 
sound but whose pulp is somewhat hyperaemic. 

At the time that Dr. Henry Head wrote his remarkable observa- 



236 THE DENTAL TISSUES 

tions on "Disturbances of Sensation, with Especial Reference to the 
Pain of Visceral Disease," Brain, Pt. Ill, 1894, and drew attention 
to certain well-defined areas of superficial tenderness of the skin, the 
study of the vascular lesions of the pulp had not been undertaken. 
His investigations were solely concerned with carious teeth, and 
showed that "As long as the pulp-cavity is not exposed the pain 
remains local. The patient will complain of an aching tooth and 
will point to the one affected." Local stimulation produces local 
pain (odontalgia), and "is exactly analogous to that produced by 
injuries to the conjunctiva or outer layers of the cornea." When, 
however, the pulp is exposed, the pain alters in character and distribu- 
tion (neuralgia). "It starts in the affected tooth, and darts or 
shoots into the face, forehead, neck, or ear" (page 407). It is 
practically certain that, to-day, increased intradental blood pressure 
in sound teeth would be added to Dr. Head's previous classification. 

Fortunately, gangrene as a permanent termination of thrombosis 
is a contingency of comparatively infrequent occurrence from a 
clinical point of view, and it is with certain atrophic changes, 
slowly produced, that the author desires to deal in the present 
chapter. 

In Chapter VII the author gives an account of that common 
lesion of the pulp which is to-day spoken of as fibroid degeneration 
or reticular atrophy. Its etiology is, there, not thoroughly eluci- 
dated. The opinion is, however (see page 188), expressed that it 
represents "the natural and usual termination of the life-history 
of the dental pulp" occurring in aged teeth. The author has 
enlarged his views on the subject, for he believes that the senility 
of the pulp does not at all depend upon its age. Children may at 
times possess senile pulps, in the same way that the eyes of young 
persons often exhibit the arcus senilis of the cornea. Much of the 
material examined for the purpose of this Chapter was removed 
for the treatment of irregularities in position of the teeth, and many 
sections show that the whole of the dentinal wall was not completely 
calcified. 

Probably this fibrosis or sclerosis is due, as a complication, in 
the first place to thrombosis of the capillaries and veins, and per- 
manent dilatation through loss of tone (due to impairment of the 
vaso-motor mechanism) or disease of the walls of the arteries, with 
or without tiny haemorrhages. This seems often to be succeeded 
or accompanied by a condensation or fibrification of the pulp tissue 
which lies between the basal layer of Weil and the substance of the 



THE VASCULAR LESIONS OF THE DENTAL PULP 



237 




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238 THE DENTAL TISSUES 

pulp proper. A hyperplasia of the connective tissue fibres of the 
parts occur. "Sheaving" of the odontoblasts, with or without 
fatty degeneration, permanent distension of the arteries and 
arterioles, and rapid development of overgrowth of the fibroid 
tissue supervene, until a well-marked reticular atrophy appears, 
and in later stages complete fibrosis of the organ, with disappearance 
of all cells and nuclei, and every vestige of nerve bundle and 
vascular system. 

HISTOLOGY 

Longitudinal coronal sections of the pulps show to the best 
advantage these changes. The capillaries and small veins which are 
distributed to the peripheral parts are engorged. Very few are 
empty and none are stenosed. Under low powers of the microscope 
they present themselves as dark long strands running for the most 
part in the vertical axis of the tooth. The corpuscles and blood 
platelets which they contain are appreciably altered in shape and 
size — due, no doubt, partly to post-mortem changes, partly to the 
histological reagents employed — as these have not been specially 
directed to the preservation and staining of the blood elements — 
and partly also to those hasmic changes which favour coagulation, 
to be presently described. They may partially or completely fill 
the lumina of the vessels, and are sometimes arranged in rouleaux; 
but in addition have in places escaped from their walls as a con- 
sequence of rupture. Small arterial cauliflower-like haemorrhages 
are seen frequently, at times among the odontoblasts, at times in 
the basal layer of Weil, and again at times in the substance of the 
pulp itself. The haemorrhagic infarcts may vary in constitution 
from a punctiform collection of a dozen or more corpuscles, to a 
large mass, as in the photomicrographs. The endothelium of the 
tunica intima of these arteries and capillaries is altered, and the 
nuclei of its cells are indistinguishable. The larger arteries and 
larger veins are empty, as exemplified, and hyaline areas of degen- 
erated material in many places extend across them, and as they 
become smaller occlude their lumina. The arteries have lost their 
distinguishing coats, and so have the veins, both classes of vessels 
having thinner walls than usual — a condition which pathologists 
would probably designate as hypoplasia or hyaline degeneration 
(Fig. 220). 

The morphological effects of these vascular lesions on the sur- 
rounding soft parts is very noticeable. In some instances the 



THE VASCULAR LESIONS OF THE DENTAL PULP 



2 39 



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MPMoMHiBJ 




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d, 




240 



THE DEXTAL TISSUES 



odontoblasts, which are largely increased in numbers, are vacuolated 
and fatty (Fig. 221, o), the globules being often situated at their 
basal extremities, very numerous, and very small as a rule, but occa- 
sionally as wide as the cells themselves. They (the cells) are flattened 
laterally, and their nuclei are planiform. They are gathered together 
into bundles or sheaves (Fig. 212). The "sheaving" of the odonto- 
blasts is of very common occurrence. It has been noticed by other 
writers, particularly by Walkhoff, who gives photomicrographs of 




Fig. 211. — Details of early fibrification of pulp tissue, d. Dentine; o. 
Odontoblasts; c. Condensation of pulp tissue; p. Early fibrosis. Magnified 250 
diameters. 

it in his "Atlas of the Pathological Histology of the Human Teeth," 
1903. The basal layer of Weil is curiously rich in small cells which 
have large round nuclei, and perhaps somewhat diminished in 
width, while its fibrous components are rendered more prominent 
and tough. 

The cells of the pulp proper possess nuclei which are degenerate 
in shape and small in size; their branches are increased in number 
and extremely well marked. Here and there, in varying degrees 
of intensity, there seems to be a thickening of the intercellular 
cementing substances and chemical changes in the cytoplasm of 



THE VASCTLAR IESIOXS OF THE DEXTAL PULP 



:_: 



the cells. When nerve bundles are visible, they appear to be degen- 
erated also, and for the time being usually stain badly as long, 
thin, dark threads running alongside the vessels- 
Organization of the thrombi is observed to be proceeding in places, 
leaving only a thin fibrous cord or hyaline plug coherent to the 
walls or completely filling it up. 




Fig. .212. — Be® 






ETIOLOGY 

Turning from the patho-histological aspect of this study, it is 
expedient and useful to inquire what possible factors have contrib- 
uted to bring about this condition. Why has the blood coagu- 
lated? Why have the vessels become thrombosed and the soft 
tissues degenerated? Probably the absence of a collateral circu- 
16 



242 



THE DENTAL TISSUES 



i 






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I \ l 14 



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;■' 4. 






'i 



m 



1 



V'i J 







m 






T ■ J 

Eft 



) • 



rq ' f\j 



t ' 



Fig. 213. — Similar to Fig. 208, showing a later stage of fibrosis of the pulp. 
D. Dentine; o. Odontoblasts increased in number; A. Arteriole; H. Hemorrhagic 
infarct; F. Fibrosis of pulp. Magnified 45 times. 



THE VASCULAR LESIONS OF THE DENTAL PULP 



243 



lation predisposes to it; but its exciting causes cannot be so readily 
determined. This absence of collateral circulation would predispose 
to the onset of thrombosis in cases, also, where any obstruction 
of outflow existed, e.g., in cases of inflammation around the soft 
parts, or inflammation in the soft tissues themselves. The vessels 
quickly become thrombosed, for instance, after the application 




Fig. 214. — Details of blood-vessels, c. Corpuscles adherent to vessel walls; 
N. Nerve bundles; P. Degenerated pulp tissue. Magnified 500 diameters. 



of arsenious acid to an exposed surface of the pulp, because the 
vessels are under hydrostatic conditions and inclosed in a resisting 
wall of dentine. Any increased volume of fluid (blood) must be 
compensated by a corresponding outpouring — as there cannot be 
an adequate displacement of the surrounding parts, owing to their 
circumscribed nature — to afford the room required. (It must not 



244 



THE DENTAL TISSUES 




Fig. 215. — Pulp in situ. B. Haemorrhage near basal layer of Weil; o. Odonto- 
blasts; D. Dentine; A. Hyaline mass in small artery; F. Fibroid pulp. Magni- 
fied 250 diameters. 



H. 



R .-■ 




Fir,. 216. — Similar to preceding (same magnification). H. Hemorrhagic 
infarct; r. Ruptured artery whence blood corpuscles have escaped; d. Dentine; 
o. Odontoblasts. 



THE VASCULAR LESIONS OF THE DENTAL PULP 



245 







Fig. 217. — Similar to preceding (same magnification), showing hsemorrhagic 

infarct. 




, 







7" ■ 



Fig. 218. — Similar to preceding (same magnification), showing hasmorrhagic 
infarct in centre of pulp tissue. 



246 



THE DENTAL TISSUES 



be forgotten, also, that no lymphatics have ever been identified as 
such in the pulp.) The thrombosis in this instance, which might 
almost be regarded as chemical or traumatic, is an early stage of 
acute inflammation, and is almost immediately followed by gangrene 
or death of the pulp en masse. 




Fig. 219. — Hyaline degeneration of blood-vessels. Magnified 300 times. 



A thrombus may be the cause or the result of arteritis or phlebitis. 
It may be due to chemical changes in the blood itself or lesions in 
the walls of the vessels, as in degenerations. Osier 1 has observed 
that in thrombus formation the blood platelets, fully investigated by 
Bizzozero, Virchow's Archives, vol. xc in 1882, and Eberth and 

1 Sir William Osier: Cartwright Lectures on the "Physiology of the Blood 
Corpuscles," 1886. 



THE VASCULAR LESIONS OF THE DENTAL PULP 



247 



Schimmelbusch, Virchow's Archives, vol. ciii in 1888, are the first 
of all the blood elements to accumulate on the vessel walls during 
coagulation, and that the filaments of fibrin spread principally 
from these plate masses. They undergo viscous metamorphosis 
and also conglutination as explained by Thoma. 1 




Fig. 220. — Thrombosis and hyaline degeneration of arteries. Magnified 500 

times. 



The thrombi formed in the sections which form the subject of 
this chapter are obviously neither entirely the "red" nor the "white" 
varieties, but are clearly for the most part of a hyaline character, 
consisting of cells, platelets, fibrin filaments, and a colourless, semi- 
transparent, homogeneous material. They are entirely non-infected, 

1 Thoma: "Text-book of General Pathology," 1896. 



2 4 8 



THE DENTAL TISSUES 



although hyaline thrombi are generally associated with infected 
conditions. 

Thus it would seem that, in the dental pulp, chemical changes 
in the blood, plus the unusual arrangement of the terminal vessels, 
assisted by the vis a tergo which naturally leads to a certain amount 




^V 



.. 1X1 



'7\ 



V. 



Fig. 221. — Details of Fig. 215 h. Hemorrhagic infarct; r. Rupture of 
blood-vessel; d. Dentine; o. Vacuolated odontoblasts; f. Early fibrosis^of pulp. 
Magnified 250 times. 

of retardation of the flow and therefore coagulation — as first pointed 
out by Virchow — are the originators of the atrophy, through loss 
of trophic influences. The chemical changes are those undergone 
by the blood through systemic derangements such as anaemia, 
chlorosis, and those which take place toward the end of exhaustive 
diseases. 



THE VASCULAR LESIONS OF THE DENTAL PULP 



249 



The suggestion of infectivity can be at once dismissed, as all the 
sections which have come under the author's notice have been 
obtained from teeth, of the young and old alike, whose macro- 
scopical aspects appeared to be sound. 

It is of course well known that the blood of chlorotic patients may 
especially tend to produce diseases of the vessel walls — due, no doubt, 




Fig. 222. — Reticular atrophy of pulp with thrombosed capillaries, h. Small 
hemorrhage near thin-walled vessel. Magnified 300 times. 



to the great diminution of red corpuscles and the relatively greater 
number of leucocytes, and their slow movement along the walls 
of the vessels, together with an increased number of platelets. 
Marantic, anaemic, and debilitated conditions which often form the 
sequelae of long-continued and enfeebling fevers and diseases, 



2;o 



THE DENTAL TISSUES 



probably also have the same or similar effects on the tissues of the 
vascular system. 

The cases here presented are entirely free from intrinsic calcifica- 
tion, are unaccompanied by the formation of adventitious dentine or 
any amyloid or fatty degeneration of the pulp; and in no specimen 




Fig. 223. — Nearly normal pulp passing into a reticular condition. Magnified 

300 times. 

yet examined by the author have there been evidences of chronic 
arteritis, atheroma or endarteritis, aneurysmal varix, phlebitis, 
or varicosity of the veins. 

CLINICAL SIGNIFICANCE 

Of what value to the dental surgeon is a knowledge of the patho- 
logical states sketched in the preceding pages? Can it assist him 



THE VASCULAR LESIONS OF THE DENTAL PULP 



2^1 



in the more perfect performance of his daily duties? Certainly; 
for it is at once obvious that if an attempt be made to "cap" an 
exposure of a pulp which happened to be diseased in this way, no 
matter how carefully or how aseptically the operation be done, 
no new secondary or adventitious dentine would be produced to 










m 




Fig. 224. — Details of thrombosis, c. Thrombosed capillary; a. Artery; n. 
Myelinic nerve bundle. Magnified 250 times. 

heal the breach of surface; and also the obstacles surrounding the 
complete devitalization of the pulp by means of arsenious acid, or 
its painless extirpation by means of pressure anaesthesia, become 
immediately manifest and indisputable. It is of course acknowl- 
edged that thrombosis and fibrosis are undiagnosable during life, 
but they may always be suspected in weak or marantic patients. 



2^2 



THE DENTAL TISSUES 




1 f* 



■4 




• 


3 


» 


SI 




Fig. 225. — General view of pulp in situ, showing an intermediate phase of 
fibroid degeneration; longitudinal median section of canine, a. Thrombosed 
artery; D. Dentine; d'. d'. Internal wall of dentine showing clefts probably 
due to molecular changes; P. Pulp tissue beginning to degenerate. Magnified 
45 times. 



THE VASCULAR LESIONS OF THE DENTAL PULP 253 

The knowledge might perhaps explain the deaths of pulps where 
no evident lesion could be ascertained. 

And, finally, it is not difficult to believe that, when the blood sys- 
tem of the pulp is deranged in the way already described, it is de- 
prived of its trophic functions with regard to the tissues around. 
Teeth lose their accustomed vitality and become more susceptible 
to outside influences and disturbances. At first remaining in 
situ, though affected by fibrosis, which exists unknown both 
subjectively and objectively, the degenerated pulp may begin 
to transmit its lowered vitality to the dentine and the periodontal 
membrane. The former most probably is deprived of its proto- 
plasmic nourishment, wholly or in part, and undergoes more or 
less chemical or molecular change, and at times morphological 
change too, as seen in the photomicrograph (Fig. 225), becoming 
unduly brittle. The latter may easily and doubtless does share in 
the fibroid degeneration, which would assuredly sooner or later tend 
to loosening of the teeth in their alveolar sockets. It may, in addi- 
tion, be hinted that perhaps this condition of lowered vitality may 
predispose the teeth to the onset of dental caries. 



CHAPTER X 

THE MORBID AFFECTIONS OF THE ALVEOLO -DENTAL 

PERIOSTEUM 

• croscopical Elements in: — (i) Inflammation; (ii) Abscess; (iii) 
Dental cyst; (iv) Innocent and Malignant tumours. 

Inflammation 

Etiology. — The causes may be divided into local and general. 
Among the first may be mentioned: (i) Extension of septic diseases 
from the pulp; (ii) Cold; (iii) Application of drugs or other irritants; 
(iv) Mechanical irritation of and infection around masses of cal- 
culus; (v) Traumatism, such as a blow, fracture, use of toothpick, 




Fig. 226. — Maxillary canine Fig. 227. — Maxillary pre- 

with chronic inflammation of molar with chronic inflamma- 
the periodontal membrane. tion of the periodontal mem- 

brane. 

etc., and (vi) Systemic. Amongst the latter: (i) Mercurial sali- 
vation; (ii) Systemic dyscrasia, e.g., gout, rheumatism, syphilis, 
struma, etc., and rarely (iii) Phosphorous poisoning. 

Synonyms. — Periodontitis, pericementitis, etc. It may be local 
or general; acute or chronic. 

Secondary Changes. — Resolution, suppuration with sometimes 
necrosis and absorption of the alveolar bone. 

Macroscopical Appearances. — The tissue is more or less thick- 
ened, rough, and blood-stained. The removal of the tooth im- 
parts to it a ragged appearance. In places it may be stripped from 
off the cementum. 

254 



DISEASES OP THE ALVEOLODENTAL PERIOSTEUM 255 

Symptoms. — When acute there is pain which is constant and dull 
in character, relieved in early stages by pressure on the affected tooth, 
but returning when the pressure is removed. The tooth becomes 
in time loosened; usually it returns to its normal firm condition. 
When chronic, pain is considerably modified; may even be absent 
until pressure is applied locally. The tooth is permanently loosened, 
and thus a great difference exists between the acute and chronic 
conditions. 

DIFFERENTIAL DIAGNOSIS OF ACUTE INFLAMMATION OF: 

The Pulp The Periodontal Membrane 

i. Pain. Sharp, shooting, intermit- 1. Dull, gnawing, aching, continuous, 
tent, throbbing, reflected. localized. 

2. Temperature. A. Cold may give 2. ^4. Cold generally gives relief. B 
relief in early stages. B. Heat in- Heat does not alter character of 
tensities pain. pain. 

3. Inspection. Tooth normal height. 3. Tooth raised in socket. 

4. Palpation. Tooth firm. 4. Tooth loose in later stages. 

5. Percussion. Negative. 5. Induces pain. 

6. Pressure. Negative. 6. At first relieves pain; in later stages, 

intensifies it. 

7. Cavity. Generally present. 7. No cavity. 

8. Pain. Increased on assuming re- 8. Not increased, 
cumbent position. 

HISTOLOGY 

The fibrous tissue is infiltrated with inflammatory cells and prod- 
ucts. These new cells collect in masses between the fibres, and are 
found running in a direction chiefly parallel with the axis of the root 
of the tooth. Inflammatory foci may form and suppurate, pro- 
ducing small localised abscesses. The osteoblasts are particularly 
visible, and depositions of new cementum with irregular lacunae and 
canaliculi often occur. Calcospherite spherules may also sometimes 
be found. The blood-vessels are dilated, and the perivascular 
tissues with their nerve bundles are considerably increased in size, 
as well as in the number of their individual elements. 



A bscess 
HISTOLOGY 

Suppurative foci of varying dimensions may occur in any part of 
the periodontal membrane. When of large size they are called 
alveolar abscesses. The inflammatory process has passed into the 



256 



THE DENTAL TISSUES 



stage of suppuration, and according to the rate of formation and the 
severity of the symptoms produces an acute or chronic abscess. In 
both cases, not only is the periodontal membrane affected, but the 
bony sockets also. When the inflammation becomes chronic, the 
membrane becomes extensively thicker, through the persistence of 
the changes occasioned by the acute condition. After extraction 
of a tooth thus affected, it is seen that large masses of soft tissue are 
adherent to the cementum. This soft tissue very frequently be- 
comes transformed rapidly into granulation tissue, with all its char- 



"■ — ■ -„iT*'*i 




p M 



Fig. 228. — Acute inflammation of the periodontal membrane in situ. Pre- 
pared by the Author's process. Stained with haematoxylene. Magnified 40 
times, d. Dentine; c. Cementum; p.m. Root membrane, the fibrous tissues of 
which are crowded with inflammatory cells and products. 



acteristic appearances and consequences. The alveolar socket 
becomes absorbed, and if the process continues, the cementum in 
addition, by the functions of phagocytes. " Granulomata " have 
been described in this connection, but nothing warrants the applica- 
tion of this appellation to the condition, when the correct definition 
of a tumour is taken into consideration (see page 327). 

Microscopical examination shows that the abscess consists of an 
outer firm fibrous sheath forming a kind of wall, the fibres of which 
run side by side in a longitudinal direction all closely interlacing. 
Stretching from these, inwards, are numbers of trabecular, composed 
of fine connective tissue dividing the interior of the cavitv into 



DISEASES OF THE ALVEOLODENTAL PERIOSTEUM 257 




Fig. 229. — The same as the preceding. Magnified 250 times, f. Connective 
tissue ("principal") fibres; 1. Inflammatory cells and products. 




Fig. 230. — Another part of the same. Magnified 250 times. 



17 



2s8 



THE DENTAL TISSUES 



septa or compartments of varying size and shape. Each is filled 
with round or squarish cells of large dimensions. In the centre of 
all, the majority of the pus cells have escaped during the extrac- 
tion of the tooth, the force of which has ruptured the wall. 




r Fig. 231. — A section*through a chronic abscess of the periodontal membrane. 
Stained with haematoxylene. Magnified 50 times. c.T. Capsule of fibrous 
tissue; m. Connective tissue cells; c. Cavity occupied by liquor pur is and pus 
corpuscles. 



Dental Cyst 

Definition. — A cystic degeneration of the epithelial "rests" of 
the periodontal membrane, produced as a result of inflammation 
of that tissue, containing some viscid fluid and holding crystals of 
cholesterine and other salts in suspension, and lined with epithelium 



DISEASES OF THE ALVEOLO-DENTAL PERIOSTEUM 259 

Etiology. — Two hypotheses are prevalent as to its origin — ■ 
(A) the mesodermic and (B) the ectodermic. 

(A) The former is based on the belief that either (i) granulation 
tissue having attained a considerable size may break down, and 
caseate, or (ii) a chronic abscess may secrete a fluid. (B) The latter 
is the theory fully investigated and described by J. G. Turner, 1 who 
has conclusively proved that minute quantities of septic products 
from the pulp cavities of dead teeth, setting up a chronic inflamma- 
tion of the periodontal membrane may stimulate to activity and 
rapid growth the paradental epithelial "rests" of Malassez ("debris 
epitheliaux paradentaires"). The central epithelial cells being cut 
off from their blood supply die, degenerate and liquefy, and a cyst 
results. 

This is most probably the correct view. 





Fig. 232. Fig. 233. 

Fig. 232. — Maxillary non-carious molar having a large dental cyst attached to 
the periodontal membrane of the buccal roots. It became displaced during the 
removal of the tooth, and, rupturing, its contents were evacuated. Mesial 
aspect. 

Fig. 233. — Same as the preceding. Buccal aspect. 

A dental cyst does not conform at all closely with the lines of 
classification enunciated by certain general pathologists. In the 
first stage of its evolution it is not derived from a distension of 
pre-existing cavities or spaces such as are a bursa, a ganglion, a 
ranula, a galactocele; it is not a cyst of new formation, like an ad- 
ventitious bursa, a hematoma, a proliferous compound cyst, a 
parasitic (hydatid) or an implantation cyst; neither is it of congenital 
derivation, as is, for instance, a dermoid cyst or a cystic lymphan- 
gioma. The important point to emphasise is that it owes its 

1 "Dental Cysts," Journal British Dental Association, pp. 711, et seq., October, 
1898. 



260 THE DENTAL TISSUES 

being to an infective condition of the tissue in which it is found, 
whereas none of the cysts enumerated above directly does. 

It has recently been shown 1 that dental cysts are not entirely 
dependent on their origin on teeth with septic pulps, as in the in- 
structive case referred to the pulp was alive. It was suggested that 
it was the outcome of spontaneous growth on the part of the same 
epithelial mass or masses. In the ensuing discussion, Mr. Turner 
expressed the opinion that it might have arisen in connection with a 
neighbouring tooth, which had been extracted fifteen years previ- 
ously to the occurrence of the cyst. Incidentally he also men- 
tioned that a cyst may originate as a consequence of inflammation 
of the periodontal membrane due to "pyorrhoea alveolaris." 

General Characteristics. — For a classification and the differential 
diagnosis of cysts of the jaws, see Chap. XV, page 401. 

Macroscopical Appearances. — On their facial aspects they present 
a smooth, oval, or round cystic tumour of different sizes according 
to the stage of growth, having a firm but elastic capsule. The con- 
tents may vary from a yellow thin liquid to a green pultaceous 
substance. 

Secondary Changes. — Inflammation and suppuration; which under 
suitable conditions may lead to spontaneous cure. It is possible 
that carcinomatous degenerations may occur. 

HISTOLOGY 

A dental cyst, after evolving from a solid collection of epithelial 
cells, consists of a connective tissue capsule or wall of varying degrees 
of thickness, 2 which encloses masses of epithelium. 

There is a small round-celled infiltration into the capsule, which 
is most pronounced near the epithelial lining. Russell's fuchsine 
bodies are sometimes present. 

The epithelium may vary in character and amount. Thus the 
cells may be round or oval with flattened nuclei, or columnar with 
spherical nuclei, or even occasionally ciliated. The presence of cilia 
has been demonstrated by Turner, Baker 3 and Rothmann. 

1 Ernest B. Dowsett, "Dental Cyst arising from the root of a living tooth," 
Trans. Odonlo. Soc. of Great Britain, Jan., 1901. 

2 In some specimens examined by the author it was 3.25 mm. in width, the oral 
mucous membrane being 0.9 mm. in width. 

5 "Notes on the Pathology of a Dentigerous Cyst," Dublin Journal of Medical 
Science, October, 1891. 



DISEASES OF THE ALVEOLO-DENTAL PERIOSTEUM 26 1 




4 * %* *» i* ™ < * •• • *_. » 1 • ,» « , 



v * * 






♦» 



Fig. 234. — Russell's fuchsine "bodies" in wall of a dental cyst. Stained with 
hasmatoxylene and fuchsine. Magnified 250 times, b. "Bodies." 




!/ E 



Fig. 235. — The interior of a small dental cyst. Stained with hasmatoxylene 
and eosine. Magnified 45 times, c. Cystic cavity; e. Epithelial lining. t w. 
Cellular infiltration of fibrous tissue of wall of cyst. 



262 



THE DENTAL TISSUES 



As regards the occurrence of ciliated columnar epithelium in 
dental cysts, Turner thinks that it may be a "reversion to type or 
a freak of growth," while Baker writes as follows: — 



c w 




Fig. 236. — A section through the entire wall of a dental cyst. Prepared by 
fixing and hardening in formic aldehyde and alcohol, and carefully decalcifying 
in a weak solution of hydrochloric acid. Stained with Ehrlich's acid haematoxy- 
lene. counterstained with eosine. Magnified 20 times. o.E. Oral epithelium; 
G. Gum tissue; p. Periosteum slightly detached from surface of the bony wall; 
b. Attenuated bone; c.w. Wall of cyst; e. Epithelium; f.s. Inner surface of cyst 
wall. 



"At first sight it seems a little difficult to account for the pres- 
ence of columnar epithelium in a position remote from the respira- 
tory tract and those other places where it is usually found: still 
if we remember the way in which ciliated epithelium is regenerated, 
its presence in my case will not be quite so obscure. It is a well- 



DISEASES OF THE ALVEOLO-DENTAL PERIOSTEUM 



263 



CE 




cc 



o s 



Fig. 237. — A section through a small dental cyst. c.w. Cyst wall; c.E. 
Ciliated epithelial lining; cc. Cyst cavity; o.s. External surface of the tumour; 
r. Extremity of root of tooth. (Prepared and photographed by A. W. W. Baker.) 



C E 




CC 



CE 



Fig. 238. — A portion of the preceding. More highly magnified. c.E. Ciliated 
epithelium; c.i. Cellular infiltration; cc. Cyst cavity. 



264 THE DENTAL TISSUES 

known experiment that when the ciliated epithelium is artificially- 
removed from a portion of the inner surface of a rabbit's trachea, 
the denuded surface speedily becomes again covered with epithe- 
lium, which grows over it from the edge. But the cells form at 
first a single layer of flattened epithelium; they next acquire cilia, 
and afterwards become columnar, the epithelium thus assuming 
the character which it has normally in that situation. If such 
transformations are possible, there is no reason why the epithelium, 
which is frequently present in the root membrane, should not under 
suitable conditions become changed into columnar ciliated." 

In amount the epithelium is sometimes merely a thin layer of 
flattened cells, sometimes a thick dense collection into which the 
sub-lying tissues send papillary eminences. 

Cholesterin, which is a monatomic alcohol and soluble in ether, 
may appear in the fluid contents as numerous, flat, minute, rhomboi- 
dal crystals each possessing one broken corner. 

Tumours 

In addition to the cystic tumour already noticed, there occa- 
sionally occur homologous neoplasms which belong to the con- 
nective tissue and epithelial groups of tumours affecting soft tissues. 
This is not surprising when the histological characteristics of the 
root membrane are recollected. Hence, the new growths, which 
are not due merely to hypertrophy of soft tissues or to inflam- 
matory changes within, may be anatomically classified as: 

A. Connective tissue tumours — 

1. Tumours of the type of fully-formed connective tis- 
sues, 

2. Tumours of the type of the higher connective tissues, 

3. Tumours of the type of young connective tissue. 

B. Epithelial and glandular tumours. 

Of these main divisions, the periodontal membrane possesses, 
as far as investigations go at present, representative growths be- 
longing to the types of 

1. Fully-formed connective tissue, e.g. Fibromata, 

2. Young connective tissue, e.g. Sarcomata, and 

3. Epithelial tumours, e.g. Carcinomata. 



DISEASES OF THE ALVEOLO-DENTAL PERIOSTEUM 



265 



i. Fibroma 

The macroscopical appearances of this benign growth arising 
from the periodontal membrane are depicted in Figs. 239, 240, 
and 241. 

A full description of these tumours will be found in Chapter XIII 






Fig. 239. Fig. 240. Fig. 241. 

Fig. 239. — Maxillary right first incisor with fibroma arising from the perio- 
dontal membrane. Distal aspect. 

Fig. 240. — Same as preceding. Labial aspect. 
Fig. 241. — Same as preceding. Mesial aspect. 



2. Sarcoma 

Oakley Coles, in 1885, was the first to draw attention to the exist- 
ence of round-celled sarcoma of the root membrane, the diagnosis 
and microscopical examination having been undertaken by Klein. 






Fig. 242. Fig. 243. Fig. 244. 

Fig. 242. — Round celled sarcoma of the periodontal membrane beginning 
between the roots of a non-carious maxillary molar. Radicular aspect. 

Fig. 243. — Another non-carious maxillary molar similarly affected to that in 
preceding figure. A more advanced condition. Radicular aspect. 

Fig. 244. — Another non-carious maxillary molar, similarly affected to that in 
preceding figure. A more advanced condition. Radicular aspect. 

And the author has observed several possible cases. There is some 
shadow of doubt that all these instances are true sarcomata. The 
close approximation of appearances presented by inflammation of 
the root membrane, makes this element of uncertainty. But it 



266 THE DENTAL TISSUES 

must be remembered that all fibrous tissues, especially those of the 
periosteum of bones, have a special predilection to undergo sarco- 
matous changes; and the clinical histories must not be ignored. 

The chief points of interest in connection with these periodontal 
tumours lie in the facts that they are found in connection with the 
roots of sound teeth, and that their characteristics are those of 
round-celled (alveolar) sarcomata. 

Seats of Occurrence. — In half-a-dozen cases which have come un- 
der the immediate observation of the author, each growth was con- 
fined, as its locus principii, to the periosteum of the molar teeth, 
the maxillary being much oftener affected than the mandibular 
series. It was generally seen to rise from a point situated at the 
junction of the roots with the body of the tooth; but it may have its 
origin from the sides of one or even two roots. Later, it generally 
fills up the whole of the interradicular region of the tooth (Fig. 
244). 

The Etiology of the disease is obscure; but there seems to be a 
predisposition on the part of the growths to attack the fibrous mem- 
branes of the teeth of women about the period of the menopause. 
Long-continued and powerful friction, as shown by the wearing 
down of the cusps, is possibly the exciting cause. 

The Subjective symptoms point chiefly to long-continued sharp 
pain, increased on pressure, the course of the disease lasting some- 
times several months. The pain is severe at times, and such as to 
render necessary immediate extraction of the loosened organ. 

Objective Symptoms. — On examining the mouth, at first there is 
sometimes almost entire absence of swelling or of any of the usual 
inflammatory signs, and the tissues are not markedly indurated. 
There may be slight suppuration. If the disease is not far ad- 
vanced, diagnosis is only complete after the removal of the tooth. 
Later, well-marked symptoms of malignancy appear. 

The tumours vary in size from a split pea to a small nut, and 
have a smooth, convoluted, rarely ragged, surface. They are 
firm to the touch, and are of a deep red colour. The teeth 
themselves are non-carious, and exhibit in their hard parts no 
traces of disease except some attrition of their cusps and (in some 
cases) absorption of the apices of the roots. They are markedly 
loose, and signs of chronic inflammation of the periosteum, accom- 
panied by an accumulation of tartar, are often noticed. 



DISEASES OF THE ALVEOLO-DENTAL PERIOSTEUM 



267 



HISTOLOGY 

The growths consist of masses of cells held together by a fine 
network of fibrous tissues which is very dense here or very loose 
there, and is in some places apparently undergoing fibrification or 
calcification. In the centre of the growth this network is scanty, 
but the intercellular tissue is conspicuous outside. Vessels are 
scanty in the centre and have extremely thin walls; they ramify 
among the cells. In the outer portion they are larger (but not 
dilated) and have normal walls. The cells themselves are for the 




Fig. 245. — A small round-celled sarcoma of the periodontal membrane. Stained 
with haematoxylene. Magnified 750 times. 

most part rounded in shape and considerably larger than red blood 
corpuscles. They contain one or more nuclei and are devoid of 
any definite cell wall (see Fig. 245). Great numbers of spindle 
cells exist. There is little haemorrhage into the tissues, proba- 
bly because of the small size of the growth, and because it has 
not advanced sufficiently to allow of large haemorrhages to take 
place in its substance; but small extravasations of blood corpuscles 
are noticed here and there. Microscopically the growth is prac- 
tically indistinguishable from granulation tissue; considered from a 
clinical aspect, however, there can be no doubt as to its malignant 
nature. A jaw, excised for malignant disease of the antrum, which 



268 THE DENTAL TISSUES 

is now in the possession of the author shows unmistakable signs 
of the sarcomatous growth beginning in the root membranes of 
the premolar and molar series, and extending into the floor of the 
antrum, and surrounding alveolar portions. It infected the soft 
tissues very thoroughly. This specimen for which the author is 
indebted to his friend the late Mr. W. J. Pilcher, was believed by 
this surgeon to originate de novo in the root membranes of the teeth 
of the patient, who was a young male adult of about 18 or 20 years. 

To sum up, it may be said that sarcomatous disease of the perio- 
dontal membrane is not rare in its earlier forms, but that it is very 
seldom met with in an advanced condition; and that removal of the 
affected tooth fortunately cuts short its career if taken sufficiently 
early, but if it is allowed to continue, it constitutes another starting- 
place for malignant disease of the maxillae. 

Less malignant, but very rare also, are tumours occasionally 
arising from the periodontal membrane, which exhibit the character- 
istic giant-cells of myeloid sarcoma. 

They will be more fully described in Chapter XIII; but here it 
may be said that while they present on the gum surface as a so- 
called myeloid "epulis," they have sometimes distinct connections 
with the periosteum of the roots of teeth. 

3. Squamous celled carcinoma 

Epithelial malignant tumours of the alveolo-dental membrane are 
very rare. But their rarity in no way detracts from the importance 
of their early diagnosis, and of the strictest prophylactic measures 
to be always taken with regard to their possible source of future 
development. 

In the Trans. Odonto. Soc. of Great Britain, June, 1901, and under 
the title of "A Case of Burrowing Epithelioma," Dr. Stanley Colyer 
has succinctly described a remarkable illustration of this affection. 
A similar case of "boring" epithelioma ("burrowing carcinoma") 
had previously been described by Sir Henry Butlin {Pathological 
Trans, vol. xxxii, 212, 1881), while Reclus, in 1876, was the first 
to note and record the condition. This is not the place for full 
references to be made to these communications. The reader is 
referred to the pages of the Transactions (pp. 231 to 242), for Dr. 
Colyer's statements. 

Nevertheless the writer here quoted may be allowed to express 
his opinion as to the possible and probable etiology of cancer of the 



DISEASES OF THE ALVEOLODENTAL PERIOSTEUM 



269 



periodontal membrane, an opinion which, it may be added, is com- 
pletely endorsed by the author. 

Etiology. — The pathological history of the case was somewhat as 
follows: — 

"The pulp was infected through a carious cavity and died; 
it then set up a suppurative inflammation around the apex. The 
pus pointed and left behind it an incurable sinus which would suggest 
— at any rate after the tooth had been sterilised — that some portion 
of the tooth was necrosed. The necrosed portion, acting as an 
irritant, would cause a hypertrophy of the stripped-up pericementum 
and a proliferation of the epithelium therein. The pain, though 
not great, would put the tooth out of use, and the pericementum, 





/ 



1 




Fig. 246. Fig. 247. Fig. 248. Fig. 249. 

Fig. 246. — Squamous celled carcinoma arising from the periodontal membrane 
of a maxillary left first incisor. The apical portion of the root was much ab- 
sorbed. Labial aspect. 

Fig. 247. — Squamous celled carcinoma arising from the periodontal mem- 
brane of a maxillary right first incisor. Labial aspect. 

Fig. 248. — Squamous celled carcinoma arising from the periodontal mem- 
brane of a maxillary left canine. Apical portion of the root considerably ab- 
sorbed. Distal aspect. 

Fig. 249. — Squamous celled carcinoma arising from the periodontal mem- 
brane of a maxillary left premolar. Mesial aspect. 



which . . was not thickened, would be functionally isolated. We 
have, therefore, got a functionally isolated pericementum in an 
otherwise healthy body, a condition which is analogous to the 
breast and uterus about the time of the menopause. According 
to this theory, then, the nice balance existing between the cells of 
the pericementum is lost, the epithelium reverts to its ancestral pow- 
ers of division, and burrows into the surrounding tissues, whose 
physiological resistance is reduced; and thus the cancer is born." 
Macroscopical Appearances. — There is practically nothing to assist 
the diagnosis of the lesion by gross examination. A soft mass of 
firm consistency arising from the periodontal membrane of a "dead" 
tooth, with or without disease of the cementum and dentine may be 



270 



THE DENTAL TISSUES 



chronic inflammation, a dental cyst (in incipient stages), a localised 
and circumscribed abscess, a round-celled sarcoma, or an epithelioma. 
Histology not only helps the differential diagnosis, but serves again, 
in a striking manner, to emphasise the dangers attendant on the 
killing of pulps in teeth, and the subsequent insufficient cleansing 
of the pulp canals. It must never be forgotten that "dead" teeth, 
unless they have undergone a rigorous course of scientific treatment, 
may seriously menace the health, or even bring about the death of 
patients. 




C N 






Fig. 250. — Epithelioma of the periodontal membrane ("Burrowing epithe- 
lioma"). Stained with Ehrlich's acid ha?matoxylene. Magnified 230 times. 
c.n. Cell-nest; c.l. Small celled infiltration of theltissues; e. Island of epithelial 
calls. " 



HISTOLOGY 



As far as the microscopical appearances of the specimens under 
consideration go, it is unnecessary to detail the various structures 
which comprise the substance of the growth. Epitheliomata agree 
in all essential particulars wherever found. For a description of 
carcinomata of the gums and palate, the reader is referred to 
Chapter XIII. The appended photomicrograph (Fig. 250) gives 
the general appearances of such a specimen. 



CHAPTER XI 

"PYORRHCEA ALVEOLARIS" 

Introductory — The gingival margin — The periodontal membrane — The 
apical region — The cementum — The bone of the jaw — Conclusions — 
Normal arrangements of the osseous and fibrous tissues — Early 
changes producing osseous atrophy — Absorption by granulation 
tissue — Chronic periostitis and senile changes — "Pockets" — Ana- 
tomical and clinical observations — Summary. 

INTRODUCTORY 

The oral diseases of which "pyorrhoea alveolaris" is a symptom 
have engaged the attention of many observers from the days of Fau- 
chard in 1746 and Jourdain in 1778 to the present time, when, more 
than ever, the whole of the medical profession, as well as the modern 
dental surgeon, has become acquainted with them in a greater 
or less degree. Next to dental caries, "pyorrhoea alveolaris" 
has especially attracted the notice of dental surgeons on account 
of its universality, its controversial character, its obscure etiology, 
its occasional difficulty of diagnosis, its recondite morbid anatomy, 
its usual intractability to treatment. It would be futile and dis- 
tinctly beyond the scope of this chapter to review, however briefly, 
the whole field of literature relating to it. In spite of all that has 
appeared it is still uncertain as to whether the flowing of pus from 
the alveolar sockets of the teeth is a local or a constitutional symp- 
tom, or both. 

Definition. — Literally — "A flowing of alveolar pus." It is a 
symptom or sign of an infective condition of the socket or sockets of 
the teeth. Purulent effusion may be limited to one tooth or may 
be general. It may exist for years localised, or rapidly spread. It 
is accompanied by a slow wasting or atrophy of the alveolar proc- 
esses of the jaws, and may be attended by the formation of tartar, 
and gradual and progressive loosening of the affected teeth. It is 
generally painless, and is not necessarily inflammatory in origin 
or in consequence. Chronic inflammations of the periodontal 
membrane frequently exist without "pyorrhoea." Synonyms are 

271 



272 THE DENTAL TISSUES 

numerous: "Rigg's disease," "interstitial gingivitis," "hemato- 
genic calcic pericementitis," so-called "periodontal disease," etc. 

Etiology. — Undetermined at present: but probably constitutional 
diseases, coupled with infection of the gum margins with pyogenic 
cocci, may briefly be considered potent factors in its causation. 
Three great schools of thought hold conflicting views on this much- 
debated question. A discussion of these would not be germane to 
the subject-matter of this book. Suffice it to say that the following, 
in a word, represent these conceptions: — 

(i) It is occasioned solely by local conditions setting up inflamma- 
tion of the gums, through the deposit of tartar, etc. A belief of 
Riggs (Trans. American Academy, 1875), Witzel (British Journal 
of Dental Science, 1882), Black ("American System of Dentistry," 
1886), 

(ii) It is due to bacterial infection — opinions of Arkovy ("Diag- 
nostik der Zahnkrankheiten," S. 232, 1885), Galippe ("Die in- 
fectiose arthro-dentare gingivitis," 1888), and Miller ("Micro- 
organisms of the Human Mouth," 1890), who found twenty-two 
varieties of bacteria in twenty-seven different cases, 

(iii) And finally, it has been ascribed to a constitutional origin 
such as gout, rheumatism, etc., theories shared alike by Tomes 
(op. cit.), Fitzgerald (Clinical Journal, 1899), Pierce (International 
Dental Journal, 1892, 1894, and 1895), and many others including 
Kirk, Burchard, and Talbot (" Interstitial Gingivitis"). 

Znamensky of the University of Moscow, with the assistance of 
Dr. Saricheff and Professor Nikiforoff, published some years ago a 
most careful paper on this subject. He was able to give an account 
of the microscopical appearances of the diseases associated with 
"pyorrhoea alveolaris," for he had obtained sections through the 
teeth and jaws of a woman suffering from alveolar "pyorrhoea," but 
who had died from another disease. This is described in the later 
portions of this chapter. 

The author has had the opportunity of making sections 
through the dental and alveolar tissues of several patients who had 
"pyorrhoea alveolaris." 1 In this chapter he proposes to put on 
record a description of this material, with the conclusions derived 
from a preliminary study of them. 

The first specimen was the right maxilla from the mouth of a 
male twenty-eight years of age. Vertical cuts were made with a 

1 The jaws were incised after death, of which the local conditions in the 
mouth were no contributory cause. 



PYORRHOEA ALVEOLARIS 



273 



diamond disk through the canne and molar teeth and an interdental 
septum, the roots of the molar being largely exposed on both the 



H 




Wa 



\ 



T"\ 







■ 



~'-\ 



Oft 



fr'A ** * 



v. 



V 






'"■■■■ ■ i J I' ■ / i 

Jit. . F XV. T ' J 










., ( 



i'v/- 



D 



■'' -''Stiff 



Fig. 251. — Vertical section through canine and right maxilla of man aged 
twenty-eight showing latest stages of extremely acute conditions associated with 
"pyorrhoea alveolaris." Lateral section, a. Apex of root formed by hyperplasic 
cementum; b. Hyperplasic periodontal membrane; c. Indifferent tissue enor- 
mously increased in amount and more vascular than usual; d. Soft medullary 
tissue exhibiting signs of hyperplasia; e. Large osteoporotic space; f. Sequest- 
rum of bone undergoing peripheral absorption; g. Osteoclasts producing lacunar 
absorption of bone of socket; h. Bone of socket partially destroyed and converted 
into osteoid tissue; 1. Line of junction of decalcified and normal bone. Mag- 
nified 35 times. 



labial and lingual sides. Macroscopic examination of these cuts 
showed that the gingival margin in the canine and first premolar 



274 



THE DENTAL TISSUES 



region was greyish in colour, believed to be due partly to blood-clot 
and partly to the presence of gangrenous tissue. The teeth were 
sound, but were slightly loose. At the deepest part of the greyish 
area a somewhat reddish line was observed, forming the border of 
demarcation between the presumably healthy bone of the jaw and 
the diseased superficial tissues. The first of these pieces was rapidly 
decalcified by immersion in aqua regia; the latter were treated by the 
Koch- Weil method of Canada balsam impregnation. 



D 




Fig. 252. — Free margin of edge of socket of labial surface of same. a. 
Cementum; b. Inflamed periodontal membrane; c. Inflamed gum tissue; D. Free 
edge of bone decalcified and converted into fibrous intervening tissue; e. Osteo- 
clasts producing lacunar absorption of external and internal surfaces of bone. 
Magnified 80 times. 

The second specimen was a portion of the right side of the man- 
dible of a patient of thirty-nine years, extending from the canine 
to the second molar inclusive. The second maxillary premolar and 
first molar had been previously extracted. Two vertical incisions 
were made through the canine and bone, and one on the mesial 
surface of the root of the second molar. The canine was found to 
have undergone attrition and was non-carious. A slight band of 



PYORRHCEA ALVEOLARIS 275 

tartar was seen on the lingual surface. This was treated by the 
Koch-Weil process. The mass, including the molar root, was 
decalcified. 

Another specimen consisted of the right maxilla of a patient of 
sixty years, from the canine to the second premolar inclusive. Two 
cuts were made through the canine. There was much attrition 
of this tooth, but no caries. Tartar was present on the labial sur- 
face. One piece was decalcified, the other hardened, after staining 
en masse, in balsam. The decalcified sections were cut on an ether- 
freezing microtome and stained with Ehrlich's acid hasmatoxylene 
and counter-stained with an alcoholic solution of eosine and mounted 
in Farrant's medium, as less likely to cause contraction of the soft 
parts. Some sections were stained by Gram's method for bacteria. 
The Koch-Weil specimens were stained with Grenacher's alcoholic 
borax-carmine. 

More material was examined, but it is unnecessary to give 
further details. 

The following description is the result of the microscopical 
examination of tissues profoundly affected by acute, later phases 
of the condition. 

HISTOLOGY 

From an anatomical point of view this may be conveniently con- 
sidered under the following headings: (I) The gingival margins. 
(II) The periodontal membrane. (Ill) The apical region. (IV) 
The cementum. (V) The bone of the jaw. This is of course an 
arbitrary distinction, but it serves to simplify the descriptions of the 
parts. 

The Gingival Margins 

The oral epithelium is apparently altered in all parts, most es- 
pecially at the periphery; here it has been lost, desquamation having 
taken place. Nearest the free edge, the cells of the stratum corneum 
and lucidum have undergone hydropic degeneration. Their nuclei 
have shrunken and many are moon-shaped in outline. In places 
where the epithelium has disappeared the papillary eminences of the 
corium remain as finger-like processes with free margins. Through- 
out there is a tendency for the epithelial cells to become confluent 
the "spiny" cells so commonly found in normal tissue being absent 
or indistinguishable. The deeper epithelial cells possess small 
round nuclei and are greatly increased in number, showing the 
phenomena of karyokinesis very markedly. 



276 



THE DENTAL TISSUES 



The submucous tissue, consisting usually of connective tissue 
fibres, is everywhere permeated by a round-celled infiltration, as 
the initial stage of an inflammation. This infiltration is most 
pronounced in the papillae of that part of the gum which is most 
closely associated with the necks of the teeth. A "pocket" has 
already been formed. The capillaries are hyperaemic and the ducts 




Fig. 253. — Apical region of same; median section, a. Apex of root with 
hyperplasia of cementum; B. Hyperplasic periodontal membrane; c. Alveolar 
bone, with many osteoporotic spaces; d. Osteoclasts. Magnified 35 times. 



of the gingival glands appear swollen and more prominent than 
usual. The great masses of inflammatory cells consist of crowds 
of polymorpho-nuclear neutrophiles, eosinophiles, lymphocytes, and 
lymphoid cells, with numerous mast cells and Unna's plasma cells. 
They are congregated into groups or clusters between the fibres 



' PYORRHCEA ALVEOLARIS 



277 



of the gum tissue and of the periodontal membrane, which are all 
somewhat coarser than usual. 

As the condition advances with the loss of the epithelium, 
the pathological changes are exaggerated to such a degree that dis- 



A - 




Fig. 254. — Vertical section through second incisor and left maxilla of woman 
aged twenty-five. Patient unaffected by disease of the bones. No "pyorrhoea 
alveolaris " present. For purposes of comparison with Fig. 253. a. Apex of 
normal root; b. Normal periodontal membrane; c. Normal alveolar bone; d. 
Normal medullary spaces and tissue. Magnified 35 times. 



integration and death of cells and blood corpuscles has taken place, 
pus cells abound, coagulation necrosis and fatty necrobiosis of super- 
ficial tissues are noted, degenerative lipogenesis has occurred, and 
the main mass has become necrotic and friable, and is undergoing, 



278 



THE DENTAL TISSUES 



H 



D 



G 

A 



N 



most superficially, liquefaction, due most probably to the proteo- 
lytic ferments as well as to the enzymes of the bacteria. Huge 
colonies of micro-organisms penetrate the tissues from the surface 
and can be seen by staining with gentian aniline violet — some of the 
masses, however, resisting the colouration and appearing under the 
16 mm. objective as deeply pigmented spots formed at the free 




e; 



F 

K 



■ 



Fig. 255. — Vertical section through another part of canine of man aged 
twenty-eight, showing destruction of socket. A. Dentine of root; B. Pulp canal; 
c. Hyperplasic cementum at apex; d. Hyperplasic periodontal membrane; e. 
Inflamed periodontal membrane; f. Sequestrum; G. Bone of external alveolar 
plate; H. Slightly inflamed gum tissues; I. Bone of internal alveolar plate; J. 
Osteoclasts producing lacunar absorption; K. Osteoporotic space; L. Osteoclasts 
producing absorption of apex of root; M. " Gitter-figuren; " N. Thrombosed vessels 
in periodontal membrane; o. Decalcified surface of g. Magnified 35 times. 



edge of the tissues. The inflammatory cells of the early stages have 
become so enormously multiplied that the nuclei are small and round, 
and soon, at the more peripheral parts, pass insensibly into the 
necrotic tissue just mentioned, which stains exceedingly feebly 
and almost possesses a ground-glass-like appearance, traces of any 
structure being absent. 

But these intense changes are secondary to, and not the cause of 
the "pyorrhoea alveolaris." 



"PYORRHCEA ALVEOLARIS " 



279 



The Periodontal Membrane 

(a) At the gingival region: Hyperemia, cellular infiltration, 
hyperplasia of the fibrous elements, increase in diameter of the 
membrane — these are the most prominent features. 

Normally measuring, in middle age, from 0.2 to 0.3 mm. in width, 
here it may extend to the enormous width of 1.0 mm., or at least 



H 



o 




Fig. 256. — Portion of same. Lettering as in preceding figure. 
Magnified 30 times. 



0.8 or 0.9 mm., the average width below being probably about 0.6 
mm. The increase in thickness is obviously due to the absorption 
of the edge of the alveolar process, which normally extends, as Zna- 
mensky says, "like a long narrow plate not containing any bone- 
marrow," of "the thickness of a piece of paper." 

(b) Lower down, that is at the cervical region, the tissue shows 
signs of a slight increase in its cellular elements by proliferation of 



280 



THE DENTAL TISSUES 



the connective tissue cells. There is no great amount of round- 
cell infiltration or leucocytic invasion. In places it is not greatly 
hyperaemic and the tissue fibres are not well marked. Gland-like 
bodies are easily seen, but are not enormous nor important. But 







. 



/ ■ 






D 



7: 









JS^ 






^ 








Fig. 257. — Gum tissue over external alveolar plate, a. Slight depth of 
"pocket"; B. Gum tissue slightly inflamed; c. Cementum; d. Normal gum tissue; 
E. Osteoclasts on surface of external alveolar plate. Magnified 80 times. - 



probably, taking it on the whole, it would be right to assume that 
there is a slight congestion of the soft parts, the main features of 
which are masked here by the strong fibrous elements. It never 
amounts to a general periostitis (periodontitis), and there is no 
granulation tissue present except in very advanced conditions. 



PYORRHCEA ALVEOLARIS 



28l 



The Apical Region 

This, which .usually measures 0.5 mm. in similar specimens, is 
now twice that thickness, filled with loosely arranged connective 
tissue fibres and the "indifferent tissue" of Black. Cells and blood- 
vessels (more numerous than normally), are increased in numbers 
and very prominent in the sections. The latter frequently branch 
and are filled with small cells. 




if 




, i 









Fig. 258. — Lacunar absorption of the alveolar bone in "pyorrhoea alveolaris." 
Stained with hcematoxylene. a. External alveolar plate which has almost become 
entirely absorbed; b. Osteoclasts on surface of a; c. Hyperplasic periodontal 
membrane; d. Thrombosed blood-vessel; e. Normal cementum; f. Dentine; G. 
Hyperplasic gingival tissue. Magnified 90 times. 



The Cementum 

The cementum, generally speaking, is hyperplasic, but not mark- 
edly so. Singularly enough its peripheral portions are remarkably 
smooth and well defined, and seldom exhibit, except at the apex 
of the teeth, the foveolae of Howship occupied by large myeloplaxes. 
If it is at all hyperplasic it is accidentally so, due to some cause 
unassociated with the "pyorrhoea alveolaris." 

There are no traces of bacterial invasion of Sharpey's fibres and 
their canals. 



282 



THE DENTAL TISSUES 



The Bone of the Jaw 

The alveolar bone exhibits even before the gum the most im- 
portant metamorphoses which have occurred. Briefly they are 
those produced by the process of halisteresis (perhaps a form of 




Ug c 



Fig. 259. — Free margin of edge of internal alveolar plate, a. Cementum; b. 
Inflamed periodontal membrane; c. Bone; d. Osteoporotic space with inflamed 
medullary tissue; e. Osteoclasts; f. Inflamed gum tissue; G. Masses of micro- 
organisms. Magnified 35 times. 

osteomalacia). Not only is the free margin of the bony socket 
absorbed by osteoclasts near the upper and lower parts of the cer- 
vical regions of the teeth, but deep down at the radicular portion, 
giving the surface an eroded appearance; moreover, there is also a 



■ PYORRHOEA ALVEOLARIS 



283 



G _ 



decalcification of the most superficial portions. The bone becomes 
transformed into an osteoid tissue through loss of its calcium salts, 
then passes into an intervening fibrous tissue and finally is attacked 
by the inflammatory exudation and cells, its bays and recesses be- 
coming meanwhile greatly enlarged and filled with loose soft tissue, 
and the Haversian canals and medullary spaces enlarged and irregu- 
lar, the condition being termed osteoporosis. 

Absorption of bone may occur in three ways: First, by the ac- 
tivities of the osteoclasts of Kolliker (myeloplaxes) ; second, by the 




G 



H 



Fig. 260. — Another portion of same. Lettering as in preceding figure, h. Free 
surface of gum from which the oral epithelium has become desquamated. 



process of halisteresis; third, by means of perforating canals. In 
the case of diseases such as give rise to the pathological conditions 
here studied, the two former are plainly going on side by side. The 
first is well understood. The second process may be described as 
being one of decalcification, the osseous matrix appearing as osteoid 
tissue. As the morbid changes progress, the osteoid tissue becomes 
more fibrillated than usual, and finally is dissolved and incorpo- 
rated in the medullary tissue. Frequently are seen the Gitter-figuren 
of Von Recklinghausen, viz., variously shaped lines or markings in 



284 



THE DENTAL TISSUES 



the bone, depending upon its dissolution by the decalcification 
agents and indicating its histodialysis (Fig. 261). 

It is truly remarkable that the alveolar portions of the periodontal 
membrane exhibit numberless osteoclasts while the cemental por- 
tion does not. It is therefore probable that this portion of the 
membrane corresponds to the inner layer of the periosteum of bones 
generally — the proliferating layer of Virchow or the cambrium of 



m 




it* «.. 



m 



<*®' 



/ 




■ 



1 &.v 





Fig. 261. — Another portion of same. A. Cementum; B. Bone; c. " Gitter- 
figuren;" d. Inflamed periodontal membrane; e. Osteoclasts. Magnified 250 
times. 

Billroth. The medullary spaces and Haversian canals throughout 
the sockets of the teeth are osteoporous — that is, have become 
eccentrically atrophic — a retrogressive phenomenon of no uncertain 
character. The same changes are occurring in the environment of 
the periodontal membrane, but not to so large an extent. 



CONCLUSIONS 



It is obvious from what has been said that the subject is vast, 
that the etiology of the flowing of pus from the sockets of the teeth 
is very debatable, and its pathology little understood. The author 



" PYORRHOEA ALVEOLARIS " 



285 



ventures to state, based on his observations of the microscopical 
appearance of sections of teeth cut in situ from jaws which were 
distinctly pyorrhceic, that — 







H 






\ > . r <o" 



' ■ < - ■ 



.-IS * 



c 



1 



<*. 



t 9 



&* 



w 1 



- 



Fig. 262. — Vertical section through canine and bone of right side of mandible 
of man aged thirty-nine. "Pyorrhoea alveolaris" not marked. Tissues over 
external aspect, a. Dentine; b. Cementum; c. "Pocket" of gum, the edge 
of which is attached to the margin of cementum; d. Slight desquamation of oral 
epithelium; E. Slight inflammation of gum; F. Edge of alveolar bone transformed 
into osteoid tissue; bone lacunae and corpuscles indistinguishable; g. Hyperplasic 
periodontal membrane; blood-vessels injected; h. Normal bone. Magnified 
35 times. 



(1) The disease of the bone is not in its earlier stages a rarefying 
osteitis. According to the most eminent authorities osteitis rare: 
faciens is "characterized by the development of vascular granulation 



286 



THE DENTAL TISSUES 



tissue of the medullary spaces and canals, associated with a lacunar 
absorption and canalisation of bone, which becomes porotic and 
soft." (Hektoen and Riesman, "A Text-book of Pathology," 



D 




if v w . <v 



\l K \ 






^a_ 



Frc. 263. — Vertical section through canine and socket of right maxilla ot man 
aged sixty. Tissues over internal aspect, a. Dentine; B. Hyperplasic cementum; 
c. Bone of jaw; no lacunar absorption, slight decalcification of free edges; D. 
Periodontal membrane hypersmic and showing signs of senile changes; e. Slight 
"pocket" at gum margin, slight gingivitis. 



iqoi; see also "A Manual of Pathology," Joseph Coats, 1900; "A 
System of Surgery," Sir Frederick Treves, 1895; article by H. H. 
Clutton, "Fungating Ostitis (Ostitis carnosa vel fungosa)," Rind- 
fleisch's "Manual of Pathological Histology," 1873; and "Rarefying 



"PYORRHCEA ALVEOLARIS " 



287 



Osteitis," in "An Introduction to Pathology and Morbid Anatomy," 
Henry Green, 1895.) 

(2) "Pyorrhcea alveolaris" does not begin as a gingivitis. 



1 







^W -J ; '* » i 



> ' 



w .i. 






m ■ ■ 



!$ r * 






--■V* 



1 • 



5 ' -V) 



, • ** > 





// 



-.. V 













££ 



****&/&& 



Fig. 264. — Same as before. Apical region of root. A. Dentine of root; B. 
Indifferent tissue enormously hyperplasic; c. Osteoporotic bone. It will be 
noticed that there is no osteoporosis at present at cervical region. (See pre- 
ceding figure.) 



(3) It is essentially dependent upon an osseous lesion, an atrophy 
o] the bone, which, in the thinnest parts, causes the cervical margins 
of the teeth to become denuded through the halisteresis and osteo- 
clastic absorption. 

(4) The pus associated with it is derived from debris of food, 



288 



THE DENTAL TISSUES 



pyogenic bacteria, and other extraneous elements, which, gathering 
in the wide pockets produced by the atrophy of the bone, may or 
may not set up ultimately a suppurative gingivitis. 




Fig. 265. — Vertical section through cervical region of molar of man, age 
unknown, which presented no symptoms of "pyorrhoea alveolaris." For purposes 
of comparison with the foregoing, and to demonstrate the fact that decalci- 
fication of edge of alveolar bone may exist before "pyorrhoea" sets in. A. Dentine; 
B. Cementum; c. Hyperplasic periodontal membrane; d. Gum tissue with deep 
gingival trough (nopus present); e. Normal gum; f. Decalcification of socket, 
no lacunar absorption. Magnified 35 times. 



(5) The presence of calculus is not sufficient in itself to induce the 
condition, and may not be associated with it at all as a predisposing 
or exciting cause. 

(6) Many cases of pus flowing from the sockets of teeth are not 



PYORRHCEA ALVEOLAR1S ' 



289 



"pyorrhoea alveolaris," but are frequently incorrectly described as 
such. 

With regard to the statement made under clause (3) it seems im- 
possible to imagine that if the gingivitis was, alone or combined 
with tartar, responsible for the pathological conditions, there could 
be no alteration in the bone at the apices of the roots, or in situations 
far removed from the surface of the gum. But this occurs; and it is 




B -■* 



Fig. 266. — The same; shows tissues over internal alveolar plate, a. Cemen- 
tum; b. Normal periodontal membrane; c. " Gitter-figuren;" d. Normal bone; 
E. Areas of decalcification. Magnified 250 times. 

believed that the gingivitis, if present, is secondarily induced, and 
that this gingivitis is produced apart from the bony lesion by haema- 
togenous infection by pus-producing micro-organisms, which, how- 
ever, have a very circumscribed area of development. 



NORMAL ARRANGEMENTS OF THE OSSEOUS AND FIBROUS TISSUES 

Examination of sections of the teeth in situ in the jaws of a woman 
of twenty-five years, whose mouth was free from any symptoms of 

10 



2 go 



THE DENTAL TISSUES 



disease, discloses the fact (Figs. 267 and 268) that the alveolar proc- 
esses vary in thickness, the bone being very narrow at the gingival 
region, broader at the cervical region, while narrowing down again 
at the radicular portion of the teeth to, roughly, about the same 
diameter as in the first-named situation. At the apices of the roots 










tk 







Wmm§§ 







jl^Jk 



Fk,. 267. — Xormal bone, internal alveolar process, from jaw of woman of 
twenty-five. A. Dentine; B. Periodontal membrane; c. Normal bone. Magni- 
fied 80 times. 

the bony socket is closely approximated to the teeth themselves, 
the periodontal membrane undergoing only very slight enlargement, 
its width remaining practically the same throughout its whole 
extent. The fibres of the gum around the necks of the teeth are not 



PYORRHOEA ALVEOLARIS 



>QI 



as densely arranged as one would expect from the statements of 
text-books. In no sense do they form a firm annular ligament, as 
described by Stohr, binding the soft tissues down to the hard parts. 
Indeed, a V-shaped space probably always exists to a slight degree 
in normal circumstances. All human teeth possess spaces — the 




*Mt& 






$MQ 




'im feu? * ■*»*^ . 

WWWm 




[Sl^ 




Fig. 268. — Same as preceding illustration, but at cervical region. Normal. 

Magnified 80 times. 

gingival troughs — around their necks, which may become potential 
cavities for the retention of micro-organisms (see Chapter X, Vol. I). 
If great care be exercised in the laboratory manipulations, it will 
be found that micro-organisms can always be demonstrated, in 
ordinary circumstances, occupying the site thus produced. It is 



202 THE DENTAL TISSUES 

when they are of the pus-producing varieties that "pyorrhoea alveo- 
laris" is established. 



EARLY UNSUSPECTED CHANGES PRODUCING OSSEOUS ATROPHY 

In the mouths of people of middle age a startling fact may be 
frequently observed. Without any signs of gingivitis whatever, 
or the presence of tartar or "pyorrhoea," when the gum tissues are 
what one would call normal and healthy and the adjacent teeth 
fully functional and free from caries, decalcification or halisteresis 
of the free edge of the osseous socket may be beginning (see photo- 
micrograph, Fig. 269). It must be remembered that the bone 
forming the dental sockets is peripheral, and — as is pointed out by 
the author in Vol. I — is structurally different from compact bone, 
properly formed, elsewhere. This ill-constructed attachment and 
foundation of the teeth easily and early falls a prey to disturbances 
in the vascular system of the jaws, and soon begins to degenerate 
and atrophy, after an acute attack of anaemia, long-continued fevers, 
rheumatism, hydrargyrism, etc. 

Investigated by the author was an affection of the mandibular 
teeth of a girl of ten years, who suffered from osseous atrophy 
associated for a few months with "pyorrhoea," which resulted in a 
permanent loosening of the two first incisors. The rest of the mouth 
was healthy. There occurred the loss of the bone of the sockets, 
and the presence of extremely deep pockets around each tooth. The 
author attributes the affection in this case directly and entirely to an 
acute attack of anaemia, following chickenpox at three-and-a-half 
years, which, in addition to producing general symptoms, acted 
locally by modifying the usual amount and character of the blood 
supply to the parts and causing malnutrition and degeneration or 
atrophy. The limitation of the condition to the two teeth named 
was probably owing to an undue amount of function, the posterior 
teeth not having erupted. Accentuated use is as bad for the teeth 
as is idleness. "Pyorrhoea alveolaris" may be confined to one or 
two teeth, when it will generally be found that they are either 
used too much — as, for instance, in holding a pipe between them 
— or to loss of function, as in the case of absence of an opponent 
in the other jaw. 

Sections of jaws with the teeth in situ which would be considered 
as normal, very frequently exhibit this atrophy of the bone. The 
result is a deepening and a widening of the gingival trough and its 



PYORRHOEA ALVEOLARIS 



293 



E -4 







Fig. 269. — Vertical section through cervical region of molar of man, which 
presented no symptoms of "pyorrhoea alveolaris." A, Cementum; B. Normal 
periodontal membrane; c. "Gitter-figuren; " d. Normal bone; e. Areas of decalci- 
fication. Magnified 350 times. 



2Q4 



THE DENTAL TISSUES 



transformation into a pocket, in which, if pyogenic bacteria happen 
to collect and develop, "pyorrhcea alveolaris" is bound to ensue. 




Fig. 270. — Mandibular molar showing absorption of one of its roots by means 
of granulation tissue developed as a consequence of chronic inflammation of the 
periodontal membrane. (See Fig. 271.) 



ABSORPTION BY GRANULATION TISSUE 

In order to further test the statement that granulation tissue— 
a part of osteitis rarefaciens — is not present in the earlier conditions, 
a lower permanent molar, with one root absorbed as a result of the 




,' - 



• ****** ~ ,-i. - ^*~- . 



t 




4* 



:■>•■., 

- - — — La 



Fig. 271. — Granulation tissue absorbing dentine. 

action of certain cells in the granulation tissue produced by an in- 
flammation of the periodontal membrane, was examined, with the 
microscopical appearances revealed in Fig. 271. 

It is important to recognise the fact that granulation tissue 



PYORRHCEA ALVEOLARIS 



295 



such as occurs in the healing of a suppurating wound, consists of a 
dense cellular new growth freely supplied with blood from capillary 
vessels of new formation. The cellular elements comprise: (a) 
Formative cells derived from pre-existing cells of varying shape and 
size; they may be oval, branched, or oat-like; their nuclei round or 
oval, (b) Polymorphonuclear leucocytes, which take no part in the 
formation of the new tissue, (c) Small lymphocytes and plasma cells 
with large, round, deeply staining nuclei, (d) Large mononuclear 
hyaline leucocytes, which, according to Metchnikoff, have the prop- 




w 







I \?: ■■•' ' ■■■■" «/■■ 

VfVWT ■■ ' ' ' " ? 



* 



\i 










Fig. 272. — For comparison. Radicular portion of firm canine, in maxilla of 
man aged forty-five. a. Hyperplasic cementum; b. Periodontal membrane. 
Magnified 40 times. 

erty of becoming metamorphosed into connective tissue cells. 
(e) Multinuclear giant cells. The latter occur in granulation tissue 
of bacterial origin (like tubercle), and in "wounds, around necrotic 
material, and about foreign bodies." In the photomicrograph the 
latter are absent. Comparison of this figure with Figs. 263 and 264 
shows the difference between the two, and demonstrates the fact 
that no granulation tissue is present in the sockets of teeth in the 
earlier stages of "pyorrhoea alveolaris," and does not necessarily 
always exist even in later stages. 



296 



THE DENTAL TISSUES 



COMPARISON BETWEEN CHRONIC PERIOSTITIS AND SENILE 

CHANGES 

Sections were cut, for further comparison, of the jaw of a male aged 
forty-five, in which the maxillary left permanent canine was firm, 
and its distal neighbour, the left first premolar, was extremely 
loose. This gave an opportunity for observing the differences in 
the microscopical appearances between the two sockets, the former 
exhibiting the usual degenerative changes of the periodontal mem- 
brane which are incidental to middle age, and the other the abnormal 







... & 



\ • 





mwA it / 

-y ... . 

' ' > ir/f 






w\ ^^^f■•d^5 




r^xj 



Fig. 273. — For comparison with preceding illustration. A. Hyperplasic 
cementum; B. Chronic inflammation of periodontal membrane; c. Fracture of 
cementum mentioned in text. Magnified 40 times. 

changes due to chronic periostitis (periodontitis). In the former 
there are no signs of inflammation; the connective tissue is increased 
in amount, and is more pronounced than in younger membranes; 
in the latter, all the histological signs of chronic inflammation are 
seen. But there is a marked variation from those of "pyorrhoea 
alveolaris." While the membrane is extremely broad, the myeloid 
cells and osteoporous spaces of the bone are wanting Incidentally 



"PYORRHOEA ALVEOLARIS " 297 

these sections also show the fracture of an extremely minute portion 
of the cementum of the premolar. 

"pockets" 

In Fig. 262 it will be noticed that the free edge of the gingival 
tissue, as represented by the oral epithelium, is loosely adherent 
to the terminal margin of the cementum; this is exhibited under a 
higher magnification in Fig. 274. The enamel has been lost, owing 
to decalcification in weak aqua regia. No hard-and-fast rule exists 
as to the cervical attachment of the gum tissues from an anatomical 
point of view. Even as the normal relationships of enamel, dentine, 
and cementum vary, so do the attachments of the soft parts. The 
"pocket" in this section is extremely slight; nevertheless, it had 
contained, during the life of the patient, a mass of micro-organisms, 
which had induced a slight suppurative gingivitis (e in Fig. 262), and 
"pyorrhoea" was actually present. At some considerable distance 
nearer the radicular region of the tooth, the usual transformation of 
the periphery of the alveolar process of the jaw had already taken 
place, the bone being converted into osteoid tissue through halistere- 
sis, although the patient was only thirty-nine years of age. This 
osseous surface was extensively decalcified by a similar process, and 
the blood-vessels in the periodontal membrane, exercising a protect- 
ive influence, were hyperaemic. When this is compared with Fig. 265, 
in which case "pyorrhoea" was absent, it is found that in the latter 
a deep and extensive pocket had been produced, the gum margin 
being attached to the cementum at a distance of 1.5 mm. below its 
free edge (see Figs. 275 and 276). It is not surprising, therefore, 
that a small-celled infiltration — which is a normal condition of the 
gum — has occurred in the immediate neighbourhood of the deep 
socket. But it is an astonishing fact that there is less pathological 
decalcification of the bone than in the preceding instance, clearly 
demonstrating that the amount of loss of the marginal bone does 
not depend upon the depth or shallowness of the pocket. It is 
important to recall that here no "pyorrhoea" whatever was 
manifest. 

It is unnecessary to lay before the reader, at present, any further 
histological details, but in support of his views, the author desires 
to add a note regarding the anatomical and clinical aspects of the 
subject. 



298 



THE DENTAL TISSUES 







Fig. 274. — Same as Fig. 262. a. Free edge of cementum; b. Oral epithelium 
of gum tissue. Above a is a shallow pocket filled with pus during life. Mag- 
nified 350 times. 



PYORRHCEA ALVEOLARIS 



299 




Fig. 275. — Same as Fig. 265. No pus present, a. Free edge of cementum. 
Gum tissue adherent below. Magnified 350 times. (See next figure.) 



300 



THE DENTAL TISSUES 



/ 




Fig. 276. — Same as preceding illustration. Gum tissue attached to cementum 

at a. Magnified 350 times. 



" PYORRHOEA ALVEOLARIS" 3OI 



ANATOMICAL AND CLINICAL OBSERVATIONS 

Absorption of each alveolar process of the jaws is a common 
occurrence; it is the rule in man and the lower animals. 1 The more 
aged the individual the greater the loss of this bone, with the con- 
comitant shedding of its dental occupants. The teeth of dogs, cats, 
monkeys, and other animals, either in a domesticated environment 
or in naturd fera, become loose as time passes by, as a direct con- 
sequence of the absorption of their sockets — a physiological process. 
Man becomes more and more inclined to be edentulous as he 
advances in life, a part of the decadence of his vital powers. Thou- 
sands of skulls of aged people exist where the teeth remain in situ. 
This is due to the splendid natural physique of the owners. But 
in probably eighty per cent, of individuals living in highly civilised 
communities, it is the normal condition for the alveolar processes 
to atrophy and shrink, for the gum tissues to become thinner and 
degenerate, and for the roots of the teeth to become exposed. 
Many cases of so-called "periodontal disease" are not the outcome 
of pathological disturbances at all, hence it follows that these senile 
changes, which may begin early or late in life, may induce, in the 
first instance, the deepening and widening of the normal trough at 
the gum margin, and then, if this is infected by pyogenic bacteria, 
"pyorrhoea alveolaris" follows. Clinically, "pyorrhoea" is un- 
accompanied by pain, i.e., generally speaking; if complications exist, 
pain may be present. As a rule, its evidences and effects are un- 
known to the patient, and its diagnosis, at times, is difficult for the 
dental surgeon. If it were produced by an osteitis rarefaciens, as 
is so generally believed, it is more than likely that all the signs and 
symptoms, objective as well as subjective, of chronic periostitis 
would supervene, and the patient would be duly warned. But 
this is not so. 

From his personal experience of cases in which "pyorrhoea 
alveolaris" was a prominent symptom, the author is led to the con- 
clusion that the morbid conditions of the jaws which produce the 
flowing of pus are not the etiological factors of severe metabolic 
disturbances of the alimentary tract or the vascular system, but 
that they are part and parcel of them. A strong infection of the 
oral cavity by means of pathogenic micro-organisms may induce 
both an extensive "pyorrhoea" in the pockets already deep enough 
to receive them, in all parts of the mouth, and contemporaneously 

1 See Appendix, Vol. I. 



3° 5 



THE DENTAL TISSUES 



a secondary toxaemia or other lesion which reacts universally on 
the bodily tissues. "Pyorrhoea alveolaris" does not initiate but is 
produced by the same septic cause which leads to general systemic 
affections, and which may set up among other diseases alimentary 
toxaemia, gastritis, enteritis, chronic toxaemia, chronic rheumatism 
and — remotely — septic anaemia, pernicious anaemia, arthritis, endo- 
carditis, septicemia, etc. 

SUMMARY 

To sum up. The course of events, in the opinion of the author, 
is as follows: Atrophy of the bony socket and shrinkage is followed 



EC\ 



I P. 



O E- 




H F 



I P 



O T 




.-= B v 



P M 



PM 



Fig. 277. 



B 
Pig. 



278. 



Fig. 277. — The gum and surrounding structures in " pyorrhoea alveolaris.'' 
Magnified 80 times, d. Dentine; c. Cementum; p.m. Root membrane; G. Normal 
tissue of the gum; B. Normal bone; o.e. Oral epithelium; E.C. Dead epithelium 
cells being cast off the ulcerated surface of gum; T. Tartar at gingival margin; 
I. p. Inflammatory cells and products. (After Znamcnsky, from the Journal of 
the British Dental Association.) 

Fig. 278. — Same as the preceding, and from the same source. Magnified 
180 times. Lettering as before, but also — o.t. Outer part of socket being trans- 
formed into osteoid tissue ; h.f. Howship's foveola^ on inside portion ; o. Osteoclast ; 
B.v. Capillary in normal root membrane. 



by a widening of the gingival margin and broadening and deepening 
of the troughs, with hyperplasia of the periodontal membrane. If 
a pathogenic infection occurs, there is a lodgment of pyogenic 
bacteria in these already suitable pockets, and "pyorrhoea" results, 
and it may or may not be accompanied by gingivitis and the produc- 
tion of tartar. 



PYORRHEA ALVEOLAR1S 303 



ZNAMENSKY S RESEARCHES 



Znamensky 1 sums up his opinions as follows: — 

1. The process in the bone is osteitis rarefaciens. 

2. The disease develops not primarily in the bone, but begins 
with a suppurative inflammation of the gums, which, approaching 
the bone, gradually produces therein the above-mentioned condition. 

3. An osteoporous form of atrophy of the sockets affords a very 
favourable nidus for its development. 

4. Exhausting diseases create in the alveolar sockets a favourable 
nidus for the development therein of "pyorrhoea alveolaris" in the 
form of an osteoporous atrophy. 

5. The lack of real hygienic care in regard to the teeth at the time 
of the foregoing constitutional diseases, and a deposition of tartar 
give rise to a suppurative inflammation of the gums, which rapidly 
passes into "pyorrhoea" on the suitably prepared nidus of the bone 
of the sockets. 

6. In slight cases, affecting only that part of the socket which 
does not contain bone-marrow, the hygienic care of the teeth — 
such as removal of tartar, washing with disinfectant and astringent 
lotions, and correct regimen of diet will alone be sufficient to suppress 
the ailment. In severe cases more stringent and radical measures 
must be adopted. 

HISTOLOGY (ZNAMENSKY) 

First steps. Irritation of the gums occurs through depositions 
of tartar, occupying the normal gingival margins. A very hard 
swollen rim of gum appears strongly infiltrated with leucocytes. 
It includes the papillary layer of the gum, the alveolar socket being 
at first unaffected. Soon the gum loses its superficial epithelium, 
and an ulcerated surface results. Emigration of leucocytes from the 
vessels takes place (see Fig. 277). 

On reaching the thin edge of bone (which in this situation does 
not possess any large medullary spaces, and therefore no marrow) 
inflammatory changes at once begin. On its free rim, which here 
attains only the thickness of a sheet of note paper, the socket loses 
lime salts, and undergoes transformation into an osteoid tissue, 
and afterwards into a fibrous intervening (uniting) tissue. This 

1 "Alveolar Pyorrhoea — its Pathological Anatomy, and its Radical Treat- 
ment." Journal Brit. Dent. Assoc, October, 1902. Also Trans. Int. Med. 
Congress, 191 3. 



304 THE DENTAL TISSUES 

loss of lime salts is shown by the homogeneous character of the bone, 
absence of lamellae, and loss of the characteristic outlines of the bone 
lacunae and canaliculi. This part is separated by a line of demarca- 
tion from the healthy part. This portion of the bony socket is 
thus transformed into a fibrous tissue, which passes more deeply 
into an osteoid tissue, which ultimately absorbs the thin bony plate 
of the alveolar septum. 

At this stage the periodontal membrane begins to be affected. 
Its blood-vessels are much dilated, and leucocytes immigrate in all 
directions. 

Destruction and removal of the thinnest portion of the alveolar 
plate are brought about thus: Under the influence of the external 
inflammation of the gum the bone becomes decalcified, then trans- 
formed into an osteoid tissue, and afterwards into a fibrous tissue, 
which is soon thoroughly infiltrated with leucocytes. 







Fig. 279. — The final stage in. the development of "pyorrhoea alveolaris." 
From the same source. Magnified 360 times. The laminae of the bony socket 
have been absorbed and transformed into "fibrous intervening tissue," infil- 
trated with inflammatory cells and products, s. Sequestrum undergoing pe- 
ripheral absorption; I. Inflammatory infiltration of the tissues. 

In those parts of the bone which contain cancellous spaces filled 
with marrow — i.e., lower down the sides of the cementum of the 
teeth — the changes just described occur, and in addition a lacunar 
absorption follows. 

This proceeds from the side of the periosteum of the socket, and 
also from the Haversian systems by means of osteoclasts in the usual 
way. The foveolae of Howship are thus produced. Small osseous 
sequestra are formed, as in Fig. 279. 

Thus, Znamensky considers that it is not produced by an atrophy 
of the sockets of the teeth. Dr. Nikiforoff, quoted by this author, 
says in his "Pathological Anatomy:" "An atrophical state of the 
bones shows itself by a thinning or disappearance of bone tissue. 
In some cases the thinning proceeds as a result of the Haversian 
canals having become widened, hence termed 'osteoporous." 



PYORRHOEA ALVEOLARIS 305 

There are two kinds of atrophy of the alveolus originating in the 
bony tissue itself: — 

(1) Simple atrophy, in which the socket disappears completely; 
the roots become denuded; there is no inflammation, and the gum 
is attached but lightly to the periosteum of the socket; and 

(2) Osteoporous atrophy, where the bone is thinned at the expense 
of the Haversian canals, which become widened ("osteoporous"); 
the gum comes up to the necks of the teeth; there is no denudation 
of the root. But the teeth begin to loosen on account of the osteo- 
porosis. There is no pus, and the gum is normal. 

To conclude. If, however, chronic inflammation of the gum, pro- 
duced by the presence of tartar as well as some wasting disease, 
occurs when osteoporous atrophy is already progressing, then 
alveolar "pyorrhoea" inevitably ensues. (Znamensky.) 



20 



CHAPTER XII 

DEGENERATION OF THE PERIODONTAL MEMBRANE 

microscopical elements ix: — (i) The fibrous and cellular tissue; 
(ii) The areolar spaces; (iii) Changes in the neighbourhood. 

INTRODUCTORY 

It would seem, prima facie, to be a matter of surprise that the 
periodontal membrane — that thin, structurally insignificant and 
uninteresting delicate periosteum that covers the roots of the teeth 
of man — should ever present many or even any pathological changes 
for examination by the dental surgeon or pathologist, or open up to 
him new fields for investigation and research, as macroscopically 
it appears so unimportant and so far beneath his serious contempla- 
tion. But second consideration reminds one that it is a fibrous 
tissue analogous, homologous, and practically identical both anatom- 
ically, physiologically, and pathologically with the periosteum of 
bones. And when this fact is recalled, and thoroughly recognised, it 
is not difficult to understand that, as a consequence of disturbances 
in or loss of the functional activity of its cellular and fibrous elements, 
or as a result of certain metabolic processes occurring therein, it 
can and sometimes does undergo metamorphoses of disintegration 
or atrophy on the one hand, or abnormal forms of growth and pro- 
liferation on the other; and that incidental to these retrogressive 
or progressive changes it may, almost as much as the periosteum of 
the jaws and long bones themselves, inflame, degenerate, or give 
origin to neoplasms of either a benign or a malignant nature. 

The progressive transformations of this tissue have been narrated 
in Chapter X. 

Degeneration of an organ in general pathology usually implies a 
gradual retrogressive alteration in its component parts, brought 
about in the first instance in one or more various ways. If cellular 
protoplasm becomes converted by an abnormal intracellular meta- 
bolism indirectly into functionless but non-necrotic and non- 
irritating tissue, and actual death does not supervene, a form of de- 
generation of the parts is established. Thus fatty, colloid, mucoid, 

306 



DEGENERATION OF THE PERIODONTAL MEMBRANE 



3°7 



calcareous, or other degenerations are types of well-known changes 
induced by conversion of the cytoplasm into several kinds of morbid 
and useless substances, and are often followed by cell-destruction; 
but the dental pulp, the periodontal membrane, and the soft parts 
found in the Haversian and medullary canals of neighbouring bones, 
seem sometimes to be able to undergo degenerative atrophy on 
which neither necrobiosis nor necrosis can possibly follow. 



p ... 



D — 




Fig. 280. — Transverse section of fibroid degeneration of the pulp, cut in situ. 
Prepared by "fixing" and hardening in alcohol and formaldehyde, and decalcified 
by the author's method. Stained with Ehrlich's acid haematoxylene. d. Dentine 
with tubules; f.o. Fibroid odontoblasts; p. Atrophied pulp tissue; Cf. with follow- 
ing figures. Magnified 170 diameters. 



■F O 



The disease about to be described is of the nature of a fibrosis or 
hyperplasia of the individual connective tissue fibres and cells of 
these soft organs — the precise clinical, histological, or pathological 
processes which have produced such results being, at present, very 
obscure and hard to trace. It is probably due to an exaggerated 
localised lack of nutrition induced by senile changes in the body 
generally — not a simple atrophy in which there is a decrease in the 
size or number of cells or fibres, but a degenerative or marantic or 



3 o8 



THE DENTAL TISSUES 



senile condition where the protoplasm and the nuclei of the cells 
are altered completely. 

Descriptions of fibroid degeneration are not generally found in 
text-books of pathology, and this probably can be accounted for by 
the fact that it seems to be limited chiefly to those vascular struc- 
tures which are situated within or between hard osseous, unyielding 
walls. 

Regarding this from a dental standpoint, these peculiar anatomical 
relationships obtain only in the mouth and jaws: in the first instance 




Fig. 281. — Transverse section of fibroid degeneration of the alveolo-dental 
periosteum, cut in situ. Prepared and stained as in preceding figure, d. 
Dentine; c. Cementum; A. Alveolar bone; M. Atrophied root-membrane. Mag- 
nified 50 diameters. 



the pulp inclosed in its dentinal environment, in the second the root- 
membrane limited by cementum internally and by alveolar bone 
externally, and again the medullary tissues surrounded so securely 
by the concentric lamellae of the Haversian systems of the alveolar 
processes of the maxillary and mandibular bones. In this manner 
the omission may be explained, but that the conditions represented 
by the term "fibroid degeneration" do exist there is no possible 
doubt whatever. 



DEGENERATION OF THE PERIODONTAL MEMBRANE 



3°9 



The author in 1802 drew attention to a frequent degeneration of 
the dental pulp which on comparison with the similar condition of 
the periodontal membrane bears a curious, interesting, and instructive 
resemblance to the latter. A casual glance at Figs. 280 and 283 shows 
that fibroid degeneration of both are almost homeomorphous. A 
reference to the etiology and patho-histology of the former will 
throw some light on the clinical and pathological histories of the 
latter. 




Fig. 282. — Transverse section of the same. Prepared as in Fig. 126. Stained 
with haematoxylene and counterstained with warm ammonia-picro-carmine. 
c. Cementum; m. Root-membrane; a. Alveolar bone; h. Enlarged (osteoporous) 
medullary spaces. Magnified 120 diameters. 



Briefly, it may be mentioned that fibrosis of the pulp is simply a 
"natural old-age termination of the life of a healthy pulp" which 
has survived any attacks of an endogenetic or exogenetic character. 
It is not dependent, in the least degree, on inflammation of that 
organ, but attendant on senile, marantic, 1 constitutional changes. 
Several writers in America and on the continent of Europe have 
described certain affections which may be allied to or even be pre- 

1 Hektoen and Riesman. A Text-book of Pathology, vol. i., 1901. 



3*° 



THE DENTAL TISSUES 




Fig. 283. 




Fig. 284. 
Figs. 283 and 284. — Transverse sections of the same. Prepared similarly. 
Stained with iron perchloride and tannic acid. c. Cementum; a. Alveolar bone; 
m. Root-membrane. Magnified 266 diameters. 



DEGENERATION OF THE PERIODONTAL MEMBRANE 



311 



cursors of this fibrosis, notably the areolation and oedema described 
by Black, the reticular atrophy of Wedl, 1 and the "Atrophia pal pee 
Scleroticans" of Rothmann. 2 

But in complete fibroid degenerations there are no cells of any 
description, no nuclei, no odontoblasts, no nerve fasciculi, and no 
blood-vessels; while the connective tissue, "which is but a loose mass 
of network in the normal state, has become grossly hypertrophied 
or quite obliterated, and its place taken by a new, firm, fibrous 




M A A 

Fig. 285. — Transverse section of the same. Prepared as before. Stained 
with hematoxylin. C. Cementum; M. Root-membrane; A. Alveolar bone; 
a. a. Structureless alveolus mentioned in the text. Magnified 160 diameters. 



structure devoid of cells, nuclei, or any regular arrangement of 
constituent parts:" see Chapter VII, Vol. II. 

There is therefore a remarkable coincidence in the microscopical 
characteristics of complete fibrification of the pulp and the root- 
membrane; but there are two important differences. One is that, 
in the pulp, the whole of the organ becomes simultaneously and 

1 Atlas zur Pathologie der Zahne, 1869. 
2 Pathologie der Zahnpulpa und Wurzelhaut, 1889. 



312 THE DENTAL TISSUES 

perhaps suddenly metamorphosed, while in the alveolo-dental 
periosteum, and in a lesser degree in the spaces of the osteoporous 
alveolar bone, the changes which lead up to a perfect fibrosis can be 
observed taking place side by side within the same area; the other, 
that whereas fibrosis of the pulp affects only that tissue, that of the 
periodontal membrane affects not the cementum, but the bone of 
the socket, which in its turn shares the innutrition of the vascular 
periosteum. It may be remarked, however, that fibrosis of the 
pulp and the root-membrane and the soft tissue in the osteoporous 
bone may occur synchronously as a result of the general senile 
changes in the hard parts of the buccal cavity. 

An examination of the mouths of elderly people often reveals, 
associated with absorption of the alveolar processes of the jaws, 
the presence of sound but aged and yellow teeth, portions of whose 
roots are exposed. The cementum is laid bare, and the periosteum 
gone. The teeth may be very loose or fairly firm, free from pain 
or afflicted with a subacute periostitis as the result of sudden trau- 
matism. Chemical or thermal stimuli yield no effect. If the 
alveolo-dental membrane of such teeth as these has never been 
subjected to disease, but has simply run its life-course and has now 
become atrophied, fibrosis has most likely occurred; and the 
microscopical study of such a membrane is rewarded by the 
discovery of certain new histological appearances which can now be 
described in fuller detail. 

HISTOLOGY 

(i) The Fibrous and Cellular Tissues 

In places the fibres are thin and delicate at the edge of the cemen- 
tum (Fig. 281), but as they unite to pass obliquely outward they in- 
crease in diameter and coarseness, here (Fig. 282) being thickly 
meshed together in broad long bundles or sheaves with but 
little branching; there, more sparse and sending out inosculating 
branches (Fig. 283). Their attachment is very strong both exter- 
nally, and their free extremities seem to be "built into" the hard 
tissues (Fig. 284). The thinner fibres are structureless, possess 
clear double contours, and branch freely. A nucleus of a connec- 
tive tissue cell may, at times, be retained, but the reticular appear- 
ance of the thinnest fibres resembles, at a glance, the stellate re- 
ticulum of the enamel organ minus its cells, at the period when it 
is about to disappear. 

As the thin fibres increase in size, it is seen that they are composed 



DEGENERATION OF THE PERIODONTAL MEMBRANE 



313 



of fine strands running parallel with one another, until in places 
they may extend across the intervening space as thick shapeless 
masses separated from one another by areolae of varying size and 
form. (Fig. 285). They pass in a wavy direction similar to the un- 
dulating character of white connective tissue fibres, and like them 
have fusiform, triangular or ovoid cells generally arranged in rows 
running parallel with the fibres themselves — that is, obliquely 
outward. Their nuclei are apparently atrophied, and do not ex- 



c — 




Fig. 286. — Transverse section of the same. Preparation and staining similar. 
c. Cementum; a. Alveolar bone; f. Fibres with degenerated cells and nuclei. 
Magnified 300 diameters. 



hibit the nucleoli or the karyoplasm or chromatin found in the same 
cells in a young periodontal membrane — facts well demonstrated 
when the sections are stained with Ehrlich's acid hasmatoxylene 
followed by warm ammonia-picro-carmine as in Fig. 282. 

These prominent aggregations of connective tissue bundles are 
probably merely the atrophied remains of the "principal fibres" 
of Black. 



3H 



THE DENTAL TISSUES 



All traces of osteoblasts have vanished absolutely, a few 
decrepit nuclei alone indicating their anatomical positions in the 
membrane; and there are no epithelial "rests" of Malassez. 
There may be a little granular detritus here and there, as also the ap- 
pearance of fatty degeneration. But this latter most likely marks 
the commencement of the areolation already mentioned. 

(ii) The Areolar Spaces 

Interesting as are these changes, the most striking point about sec- 
tions of fibroid degeneration are the areolae newly developed in the 




Fig. 287. — Longitudinal section (apical region) of fibroid degeneration of the 
alveolo-dental periosteum. Preparation, staining, and magnification as in Fig. 
285. D. Dentine; c. Cementum; a. Alveolar bone; M. Root-membrane; G. Gum 
tissue. 



tissue. In many instances they extend right across the thickness — 
or rather the thinness — of the periodontal membrane (see Figs. 
281 and 287). The larger ones measure 310,1* and more, the smaller 
2/i to 20//, the average being perhaps 60/z. 
They are found in great numbers, they vary in shape, being 



DEGENERATION OF THE PERIODONTAL MEMBRANE 



315 



tubular, oval, or round, and they are bounded and supported by 
strong curved fibres which pass almost circularly around them. They 
are in no sense the remains of the blood-vessels, as they are not con- 
fined to the central zone of the membrane, which is. more or less, 
the rule in normal conditions. In addition they do not possess the 
definite walls of arteries, veins, and capillaries. They are perhaps 
more marked and obtrusive in transverse than in longitudinal sec- 
tions (Fig. 286). Distributed fairly evenly throughout the mem- 
brane, they extend into the recesses of the osteoporous alveolus. 




Fig. 288. — Transverse section of the root membrane of an aged tooth. Prepa- 
ration, staining, and magnification as in Fig. 281, d. Dentine; c. Cementum; 
m. Root membrane; a. Alveolar bone. Cf. cementum in Fig. 281. 



The width between the bone and cementum is but little di- 
minished, and differs thus from mere senile changes (Figs. 288 and 
289). It measures in its thinnest portion about 150/z. But it is a 
noticeable feature of these sections that the bays or recesses of the 
alveolar bone are more exaggerated — doubtless not through absorp- 
tion, as in the case of old teeth affected by "pyorrhcea alveolaris" 
(see Figs. 290 and 291), but on account of the general osteoporosis 
which has occurred. 



316 



THE DENTAL TISSUES 



(iii) Changes in the Neighbourhood 

It is a noteworthy fact that the cementum, although slightly 
thicker than normal, is not hyperplasic, the majority of the sections 
cut by the author being free from lacunae and canaliculi (Figs. 281, 
284, 286, and 292). 

The osteoporosis of the alveolus is very pronounced, and the en- 
larged Haversian canals are filled with a shrunken fibroid tissue of a 




Fig. 289. — Transverse section of periodontal membrane of the tooth with 
acute "pyorrhoea alveolaris, " from the mouth of a man aged seventy-one years. 
Prepared and stained as above, c. Cementum; a. Alveolar bone; m. Root-mem- 
brane; b. Blood-vessels; o. Osteoblasts. Magnified 260 diameters. 

character resembling that which is found between the ''principal 
fibres" of the root membrane. Most of these spaces in the bone, 
which are usually rounded, exhibit one or more large coarse areola 1 , 
possibly and probably the remains of the vascular system (Fig. 
293). There are no red marrow cells, no myeloplaxes, no connective 
tissue cells, no blood corpuscles — nothing but an innutritious non- 
typical reticulum of coarse and fine fibrous bundles. 



._ B 



DEGENERATION OF THE PERIODONTAL MEMBRANE 317 





■DC 



* 



:*. 



C- 



ft 



Fig. 290. — Same as preceding, c. Structureless cementum; d. Dentine; oc. 
Osteoclasts. Magnified 220 diameters. 




■ M 



Fig. 291. — Same, prepared by Weil's balsam method, d. Dentine; c. 
Structureless cementum; M. Root-membrane; A. Osteoporous alveolus; F. How- 
ship's foveolae, produced by absorption by means of the osteoclasts. Magnified 
120 diameters. 



3i8 



THE DENTAL TISSUES 




Fu;. 292. — Transverse section of fibroid degeneration of the alveolo-dental 
periosteum. Stained with iron perchloride and tannic acid. Shows the general 
appearance of the tissue. Magnified 50 times. 




H 



— C 



Fig. 293. — Osteoporous alveolar bone. Stained with haematoxyline. c. 
Concentric lamellae; 1. Intermediary lamellae; h. Enlarged Haversian canal or 
cancellous space; f. Fibroid degeneration of the medullary tissue; b. Atrophy of 
artery (?) Magnified 250 diameters. 



DEGENERATION OF THE PERIODONTAL MEMBRANE 3 10, 

The lacunae of the Haversian systems are generally speaking 
abrachiate; and that part of the bone itself which is immediately 
contiguous to the periodontal membrane has undergone micro- 
scopical alteration and degeneration in which the structure of the 
concentric and intermediary lamellae are not only masked, but in 
some instances entirely lost and unrecognisable (see Fig. 285). 

There is no calcificat'on of any of the parts of the root membrane, 
no progressive ossification or osteoplastic signs, no attempts at 
ankylosis; everything points to retrogressive changes pure and 
simple. 

It would be indeed surprising if, all the other soft tissues degen- 
erating as has been seen, the gum in the immediate vicinity should 
escape. It does not, but partakes, in its turn, of the general effects 
of the loss of nutrition (Fig. 287). It is only necessary to add that 
it becomes much attenuated both in its epithelial and sub-epithe- 
lial portions, more coarsely fibrous and less vascularised than usual, 
and may, wholly or in part, undergo fatty, fibroid, or other old-age 
changes. 



PART II 



THE ORAL TISSUES 



21 



CHAPTER XIII 

THE PATHOLOGICAL CONDITIONS OF THE GUMS, 
PALATE, ANTRUM, AND JAWS 

Microscopical Elements in: — (i) Inflammation of the gum; (ii) Hyper- 
trophy of the gum; (iii) Fibroma; (iv) Spindle-celled sarcoma; (v) 
Round-celled sarcoma; (vi) Giant-celled sarcoma; (vii) Melanotic 
sarcoma; (viii) Endothelioma; (ix) Papilloma; (x) Hsem-angioma; 
(xi) Osteoma; (xii) Adenoma; (xiii) Carcinoma; (xiv) Syphilis; (xv) 
Inflammation and carcinoma of lining membrane of the antrum of 
Highmore; (xvi) Tumours of the jaws. 

The following diseases of the soft parts of the buccal cavity and its 
accessory sinus are among the more common affections which come 
under the immediate notice of dental surgeons. It is not easy to 
arrange them in anatomical order, and their classification in an alpha- 
betical list is inconvenient. They are here briefly described from 
the clinical and pathological standpoints, which, it is hoped, will be 
of service to the reader. 



OF THE GUMS AND PALATE 

(i) Inflammation of the Gum 

Inflammation of the gum {gingivitis) may be acute or chronic, 
diffuse or local (marginal). 

Causes. — Chronic irritation from the presence of foreign bodies 
such as tartar, edges of fillings, ill-fitting metallic crowns or clasps. 
"The blue line" of chronic lead poisoning is a chronic general 
gingivitis. 

HISTOLOGY 

The soft tissues are infiltrated with inflammatory cells and pro- 
ducts. The oral epithelium may be unaffected and the terminal 
free edge of the alveolar process, at first is unabsorbed. The vessels 
are hyperasmic. 

322 



DISEASES OF THE GUMS AND JAWS 



323 




Fig. 294. — Acute gingivitis round a loose second incisor in mouth of a woman 
aged fifty. Stained with ha^matoxylene and eosine. d. Dentine; c. Cementum; 
B. Edge of alveolar bone ; e. Oral epithelium; g. Inflamedgum; p. Periodontal 
membrane. Magnified 45 times. 



3 2 4 



THE ORAL TISSUES 



(ii) Hypertrophy of the Gum 

GENERAL CHARACTERISTICS 

Definition. — A non-inflammatory localised increase of the sub- 
stance of the gum, chiefly apparent round the necks of the teeth, 




Fig. 295. — The same as the preceding figure. Magnified 200 times, o.e. 
Oral epithelium; c. Cellular infiltration of the sub-mucous tissue. 

due to augmentation of the size or of the number of its cells, or of 
both, without any appreciable alteration in its structure. Syno- 
nym: "Polypus" of the gum — an illiterate term. 



DISEASES OF THE GUMS AND JAWS 



3 2 5 



Its etiology is but imperfectly understood. Some forms, occurring 
in the mouths of young children, suggest congenital origins; but 
acquired forms are certainly due to functional increase and nutri- 




A B 

Fig. 296. — A mandibular molar presenting a true hypertrophy of the gum 
associated with the periodontal membrane at its cervical margin, a. Shows the 
new, pedunculated growth, dislodged from the carious cavity into which it had 
extended — thus simulating a chronic hyperplasic inflammation of the pulp, and 
its periosteal attachment, b. Shows the position it occupied normally in regard 
to the tooth itself. 

tive supply from any cause whatsoever. Localised hypertrophies 
are often induced by local irritation, as from tartar, "pyorrhoea 




Fig. 297. — Hypertrophy of the gum. Prepared by "fixing" and hardening 
in formalin and alcohol. Stained with Ehrlich's acid hasmatoxylene. Mag- 
nified 45 times, o.e. Oral epithelium; s. Submucous tissue. 

alveolaris," etc. Such cases are not true examples of the condition, 
but may be termed "inflammatory hypertrophies." 



326 



THE ORAL TISSUES 



HISTOLOGY 

The mucous membrane is generally unaffected, and the sub- 
mucous tissue may project into it in the form of papillae, or these may 
be absent. 

The bulk of the tumour is composed of connective tissue fibres, 
which, somewhat coarser than usual, interlace in every direction. 
While, in some instances, the vascular system is largely increased in 
the sub-epithelial regions, the cellular elements, scanty in the nor- 
mal gum, are much multiplied. Here are found many connective 
tissue cells, crowds of leucocytes (polymorphonuclear neutrophiles, 




Fig. 298. — Similar to the preceding. Preparation, staining and magnification 
the same. c. Coarse connective-tissue fibres. 

eosinophiles and lymphocytes), some mast cells (M astzellen), many of 
the plasma-cells of Unna, and many lymphoid cells. The leuco- 
cytes are seen in the tissue spaces, around the blood-vessels, and 
lie between the coarse fibres of connective tissue. Unna's cells may 
be scattered throughout the substance of the growth, and the mast 
cells (whose granules are capable of becoming specifically stained by 
means of the basic aniline dyes, e.g., gentian aniline violet), can be 
noticed at the advancing margins of the new growth. 

In addition, sections will sometimes show clusters of cells which, 
at first sight, resemble the epithelial cell-nests which are patho- 



DISEASES OF THE GUMS AND JAWS 



327 



gnomonic, when found in certain situations in carcinomata, mixed up 
with lymphoid cells and a certain amount of fat cells. 

Roe, of Philadelphia, examined sections of hypertrophy of the 
gum from a bacteriological standpoint, and found, 1 on using Weig- 
ert's staining method, many saccharomyces present in the tissues. 

He concludes (p. 350): — "The pathology indicates 

that this disease is not a true hypertrophy, but should be classed 
with the infectious granulomata; and, in keeping with the established 
nomenclature, I would propose calling it Saccharomycosis, caused by 
saccharomvcetes." 



TUMOURS OF THE GUMS AND JAWS 

Definition. — A tumour is a new growth, not produced by inflam- 
mation or mere hypertrophy of pre-existing tissue, which shows no 
tendency to undergo spontaneous cure or yield to the action of drugs. 

A homologous tumour resembles and grows in the tissue in which it 
originates; e.g., fibroma of the periodontal membrane. 

A heterologous tumour originates in one type of tissue and retain- 
ing the features of that type, invades and replaces another type; e.g., 
carcinoma of the gums, palate, etc. 

Clinically, it is either (1) innocent or malignant, and (2) cystic or solid. 

Innocent or benign tumours, differ from malignant tumours in the 
following particulars: 

Differential Diagnosis of 



Innocent tumours Malignant tumours 


i. Grow slowly. 


1. Grow rapidly. 


2. Resemble fully-formed tissues. 


2. Do not. 


3. Encapsuled. 


3. Non-encapsuled; infiltrate neighbour- 
ing structures. 


4. Movable. 


4. Fixed. 


5. Lymphatic system not involved. 


5. Involved. 


6. No dissemination in distant organs. 


6. Spread by embolism. 


7. No constitutional symptoms. 


7. Cancerous cachexia. 


8. No recurrence after removal. 


8. Often recur. 



1 The Dental Cosmos, p. 347, 1901. 



328 



THE ORAL TISSUES 



Histologically, tumours are classified as 
I. Connective tissue tumours. 

A. Fully-formed connective tissue type, e.g., fibrous, fatty, 
cartilaginous, osseous, etc. 

B. Complex connective tissue type, e.g., blood-vessels, lymph 
vessels, etc. 

C. Young or embryonic tissue type, e.g., round cells, spindle- 
cells or giant cells. 

II. Epithelial and Glandular tumours. Squamous, spheroidal, or 
cylindrical (columnar) type. 
111. Teratoma. A rare tumour, generally of the ovaries, containing 
teeth, hair, pultaceous secretions, etc. See Chapter XVII. 
They are thus named: 
I. A. Fibroma, lipoma, enchondroma, osteoma, papilloma, etc. 

B. Angioma or hemangioma or nevus, lymph-angioma, 
lymphadenoma, endothelioma, etc. 

C. Round-celled sarcoma, spindle-celled sarcoma, mixed-celled 
sarcoma, giant-celled or myeloid sarcoma. 

II. Squamous-celled carcinoma or epithelioma. Cylindrical-celled 
carcinoma. 
Adenoma. 

Differential Diagnosis of 



Sarcoma Carcinoma 


i. Youth and early age. I. Old age. 



2. Each cell is completely surrounded by varying 2. Cells in alveolar spaces; 
amount of intercellular material, which does blood-vessels ramify in con- 



not form alveolar spaces; blood-vessels ramify 
amongst the cells. 



nective tissue stroma. 



3. Disseminates by blood-vessels* (veins). 


3. Disseminates by lymphatic 
system. 


4. Haemorrhages frequent. 


4. Haemorrhages infrequent. 



INFLAMMATORY AND NON-INFLAMMATORY SWELLINGS OF THE JAWS 

These may be classified as arising in 
A. The Maxilla: 

1. Those involving the maxillary sinus. 

2. Those involving the alveolar process. 

3. Those involving the palate. 

* Except in the case of the tonsil, testis, and thyroid body. 



DISEASES OF THE GUMS AND JAWS 



329 



B. The Mandible: 

1. Those arising from the mucous membrane and periosteum. 

2. Those arising between the external and internal alveolar 
plates. 

A 
SWELLINGS OF THE MAXILL.E 

I. Swellings of the antrum are 

1. Those arising locally: 

(a) Fluid — mucous cyst. 

(b) Solid — adenoma, sarcoma, carcinoma. 

2. Those arising by invasion: fibroma, enchondroma, osteoma, 
round, spindle-celled and melanotic sarcoma, carcinoma. 



Differential Diagnosis of Fluid Swellings of Alveolar Processes 



Acute 
abscess 


i r ™ Dental cyst 
abscess J 


Follicular Epithelial 

odontome 1 X t ™„ 

(simple) \ odontoma 


I- Age 

f 


Any. 


Any. 


Adult. 


Child. 'Young adult. 


2 . Pain 


Great. 


Not great. 


Slight on 
pressure. 


None. 


None. 


3. Rate of growth. 


Rapid. 


Rapid at 
first; varies. 


Slow; Slow; Very slow, 
progressive progressive 


4. Appearance of 
mucous membrane 


Acutely 
inflamed. 


Inflamed. 


Normal. 


Normal. Normal. 


5. Definition 


Large area. 


Small area. 


Small area ; 
globular 
outline. 


Large area; Large area; 
well not well 
defined. defined. 


6. Walls 


Thin. 


Thick. 


Very thin. Very thin. . Thin. 


7. Fluctuation. . . . 


Non-elastic 


None. 


Elastic, t Elastic. None. 


8. Tooth 


Carious 
and septic. 


Carious 

and septic. 


"Dead." Absent. 


Absent. 


9. Radiograph. . . . 


Outline 
clearly 
defined. 


Outline 
not so 
clearly 
defined. 


Very clear 
outline. 


Good 

definition; 

tooth in 

cavity. 


Not very 
good defini- 
tion; tooth 

generally 
absent. 



33° 



THE ORAL TISSUES 



II. Swellings of the alveolar processes are 

i. Those arising from surface — fibroma (so-called "epulis"). 
2. Those arising from interior: 

(a) Fluid — acute abscess, chronic abscess, dental cyst, follicular 
odontome, epithelial odontome. 

(b) Solid — fibroma, calcified odontome, sarcoma, carcinoma. 
III. Swellings of the palate are 

(a) Fluid — acute or chronic abscess from second maxillary 
incisor, dermoid cyst of soft palate. Rarely, simple folli- 
cular odontome, and aneurysm of descending palatine 
artery. 

(b) Solid — innocent tumours, viz., fibroma, papilloma, 
adenoma, osteoma. Malignant tumours, viz., sarcoma 
and carcinoma. 



Differential 


Diagnosis of 


Solid Swellings of the Palate 




Rate of growth 


Characteristics 


Frequency of 
occurrence 


Situation 


Fibroma 


Slow. 


Pedunculated. 


Common. 


Osteoma 

(Torus palatimis) 


Exceedingly 
slow. 


Flat. 


Common. 


Hard palate. 


Adenoma 


Slow. 


Sessile. 


Rare. 




Sarcoma 


Very rapid. 


Hard palate. 


Carcinoma 


Very rapid. 




Soft palate. 



B 



SWELLINGS OF THE MANDIBLE 

i. Of mucous membrane or periosteum: fibroma, enchondroma, 

osteoma, sarcoma and carcinoma. 
2. Of interior: 

(a) Fluid — acute and chronic abscess, dental cyst, follicular odon- 
tome, epithelial odontome. 

(b) Solid — sarcoma (usually myeloid), squamous-celled carcinoma. 



DISEASES OF THE GUMS AND JAWS 
Differential Diagnosis of Swellings of Exterior 



33* 





Situation 


Skin or mucous membrane 


Fibroma 


Median line. 


Not involved. 


Enchondroma 


Inner side in premolar 
region. 


Not involved. 


Osteoma 


Inner side in premolar re- 
gion, or at angle. 


Not involved. 


Sarcoma 




Ulcerates primarily or sec- 
ondarily. 


Carcinoma 




Ulcerates primarily. 


For further signs and symptoms, see above. 

Differential Diagnosis of Swellings of Interior 




Rate of growth | Extent 


Appearance 


Fluid 


Slow. 


Involves outer plate. 




Solid 


Rapid. 


Involves both plates. 


May simulate 
necrosis of bone. 



The salient histological characteristics of the above tumours must 
now be described. 



I. TUMOURS OF THE FULLY-FORMED CONNECTIVE TISSUE TYPE 

(iii) Fibroma 

GENERAL CHARACTERISTICS 

Definition. — A connective tissue tumour of the homologous 
type, arising from the osseous tissues (or their periosteum) of or 
underneath other parts of the buccal cavity. Synonym: "Fibrous 
epulis." 

The term "epulis" (ext upon, ov\a the gums) is often carelessly 
applied to a true fibromatous type of neoplasm which is of constant 
occurrence. "Epulis" simply means "upon the gum,' J and if 
used at all should have before it a qualifying adjective, such as 
"fibrous," "sarcomatous," &c. Employed per se, it should be 
deleted from all dental vocabularies. 



2,2,2 THE ORAL TISSUES 

Etiology. — Congenital influences probably have some share in the 
formation of these growths; and it is just possible that traumatism 
may occasionally give rise to them. 

With regard to the first hypothesis, it has been suggested 1 that as 
far as the mandible is concerned they may have their origin in some 
embryonic "rest," left at the time of fusion of the two halves of 
Meckel's cartilage; and as far as the palate is concerned, they may 
take their rise from the sutures existing in the foetus, between the 
premaxillary and maxillary bones. This theory thus corroborates 
J. G. Turner's researches on the subject. 




Fig. 299. — Fibroma of the jaws, rising from the interdental osseous septa. 
Prepared, stained and magnified as in Fig. 297. The "hard" variety. 

Situation. — Fibromata are usually found between neighbouring 
teeth, which may become separated, or springing from the labial 
or buccal surfaces of the gum covering the alveolar processes of the 
jaws. Arising from and rarely attached to the periodontal mem- 
brane, they may be removed during the extraction of teeth (see Figs. 
239, 240 and 241). They are often associated with the periosteum 
of the interdental septa or that of the jaws. 

1 J. H. Targett, "The Pathology of certain growths about the Lower Jaw." 
Trans. Odonto. Soc. of Great Britain, May, 1902. 



DISEASES OF THE GUMS AND JAWS 



333 



Pathology. — In the mouth, as elsewhere, two kinds may be found — 
the soft and the hard. They differ in that the former is much more 
vascular, and has its constituent parts more loosely arranged than the 
latter. They agree in the following particulars: — 

In shape they are circumscribed masses roughly spherical or oval 
in outline. They may be sessile or pedunculated, nodular, or 
flattened. 

Varieties. — Classified pathologically, they are called "periosteal" 
and "endosteal." Of firm consistency, on sectionising they show, 




Fig. 300. — The same. Magnified 250 times. 

when examined in the gross, a white glistening surface, with strong, 
pale bands of connective tissue fibres. 

In the mouth they are usually single. 

Secondary Changes. — Superficial ulceration, and calcification, 
wholly or in part. Rarely hydropic degeneration of the epithelium 
may occur, and lead ultimately to malignancy. See Chapter XIV. 

HISTOLOGY 



Sections of hard fibromata exhibit dense bundles of connective 
tissue fibres (mature normal fibrous tissues), which interlace in all 



334 



THE ORAL TISSUES 



directions, but in the sub-epithelial region are arranged concentric- 
ally. The blood-vessels are few in number, and lymph-spaces are 
scanty. The cells have laterally flattened nuclei, and are practically 
spindle-shaped in outline. 

The soft varieties have a somewhat embryonic aspect, as that of 
newly forming connective tissue. The vessels are large and nu- 
merous. The cellular elements, with large round or oval nuclei, 
abound in great quantities. 




Fig. 301. — The same, showing some of the characteristics of the "soft" variety. 

Magnified 45 times. 

Normal mucous membrane is present on the surface of both 
varieties, but the sub-epithelial papillae show signs here and there 
of variations from the normal type. "Spiny" cells are constant. 



(iv) Spindle-celled Sarcoma 

This is one of the commonest forms of sarcoma, and may be hard 
or soft. The spindle-celled tumours of the gums may be quite be- 
nign, or may pursue a malignant course, and have a remarkable 
capacity for embolic dissemination. 

Definition. — A malignant tumour, the commonest of the sarcomata, 
which is composed of spindle-shaped cells varying in size, and con- 



DISEASES OF THE GUMS AND JAWS 



335 



taining one or more nuclei. It is less malignant than the round- 
celled varieties, at first may be encapsulated but later infiltrate the 
surrounding tissues. The cells are embedded in a scanty amount of 
intercellular material. The tumours may arise in the periosteum of 
the jaws or the alveolo-dental periosteum, and at times in the dental 
capsule. Rarely they are endosteal in origin. 

Varieties. — (i) Small spindle-cells; (2) large spindle-cells. 

Secondary Changes. — Fibrification, fatty degeneration, small blood 
cysts, ossification and ulceration if the gingival tissue is involved. 




Fig. 302. — Hard fibroma of the hard palate, showing the coarse nature of the 
growth. Magnified 250 times. Cf. Fig. 300. 



HISTOLOGY 

The cells are much elongated, with long tapering polar processes. 
A supporting stroma is often indistinguishable, so closely set are the 
cells. There may be two kinds of these, small and large, as in the 
round-celled sarcomata. 

In the former the constituent parts are uniform in size and ap- 
pearance, while the latter display many features of polymorphism, 
round and oval cells being inextricably mixed with the rest of the 
tissues. A photograph of such a tumour, which, in spite of due 
surgical precautions, constantly recurred locally after removal, is 
shown in Fig. 303. 



336 



THE ORAL TISSUES 



The nuclei are usually ovoid, with a small amount of karyoplasm. 
When the cells are large, however, this nuclear network is abundant 
and fully developed, and may contain one or more nucleoli. In 
places, giant cells may be produced by segmentation of the cell 
nuclei. 

The new blood-vessels are merely endothelial tubes surrounding 
the sarcomatous cells. The pre-existent vessels of the supporting 
reticulum are probably those arteries, veins, and capillaries which 
possess well-defined walls. 









f* 





-**'-* 1 #■?**■* 

>. .« M. 




Fig. 303. — Recurrent sarcoma of the jaws. Magnified 250 times. 



(v) Round-celled Sarcoma 

Definition. — A malignant tumour which resembles in structure 
most immature connective tissue. 

This genus of tumour is of a softer consistency than that just 
described. It closely approaches the type of embryonic tissue. 
It is more malignant than the preceding. Originating in the 
periosteum of the bones of the jaws, it may invade the antrum or 
attack and absorb the alveolar processes. 

In this division two varieties are also found, large and small- 
celled. In the former polymorphous elements may be discovered: 
epitheloid and endotheloid cells, arranged in localised masses, and 
divided from one another by a distinct stroma, may occur, and by 



DISEASES OF THE GUMS AND JAWS $37 

their mode of arrangement give to this form of tumour the name of 
"Alveolar sarcomata." (Billroth.) These, endothelial in origin, 
ought really to be classified amongst the endotheliomata. 

It is very difficult histologically to differentiate between young 
granulation tissue and small round-celled sarcomata. The history 
of the case and the clinical evidence here weigh very heavily in 
deciding the pathology of the growth and the course of treatment 
to be adopted, as well as in the general prognosis. 

Secondary Changes. — Fatty degeneration or minute haemorrhages. 

(vi) Giant-celled Sarcoma 

Definition. — A malignant tumour containing giant-cells. 

As has been pointed out, myeloid cells may occur at times in 
the large-celled varieties of spindle and round-celled sarcomata. 
But giant-celled sarcomata are really those neoplasms not uncom- 
mon about the jaws (especially the mandible) of children and young 
adults, in which giant-cells are a distinguishing feature both with 
regard to size and number. They are the least malignant of all 
the sarcomata. 

Synonym. — "Malignant 'epulis,' " or myeloma. 

Etiology. — These tumours arise probably either from the peri- 
osteum of the jaws or the cancellous bone of their interiors. The 
method of formation of the large masses of protoplasm is obscure. 
Some of them may possibly be regarded as phagocytes (occasionally 
blood pigments and other chemical products may be found enclosed 
in their protoplasm) ; others possibly have their origin in the fusion 
or confluence of smaller endothelial cells. 

Secondary Changes. — Small numerous haemorrhages. 

It most frequently occurs in connection with bone, is of slow 
growth, and seldom recurs after removal, in consequence of the fact 
that it does not invade the lymph nodes nor become disseminated by 
the blood stream. In the maxilla it arises in the alveolar processes, 
or the facial wall of the antrum: in the mandible in the alveolar 
processes, generally (in both jaws) in the region of the second pre- 
molar or first permanent molar. 

HISTOLOGY 

Myeloid sarcoma consists of dense firm masses of round or spindle 
cells contained in a small amount of fibrous stroma, and possessing 
large multi-nucleated cells in abundance. 



338 



THE ORAL TISSUES 




Fig. 304. — Two myeloid cells in a myeloid sarcoma attached to the periodontal 
membrane and bony socket of a molar. Magnified 500 times. 




Fig. 305. — The same, magnified 750 times. 



DISEASES OF THE GUMS AND JAWS 



339 



These cells vary in shape in different parts of the growth, and con- 
tain varying numbers of small nuclei — as many as two or three 
hundred have been counted — or a few large nuclei or even one large 
nucleus, showing no evidence of subdivision. They may be vacuo- 
lated, and are usually surrounded by clear spaces of different width, 
the result of rapid shrinkage during the fixing and hardening of the 
soft tissues (see Figs. 304 and 305). 







; • 

1 i 




■ * 


: % 


••A 


* 'mm 


HHSfCkv' 







Fig. 306. — Melanotic sarcoma. Stained with haematoxylene and eosine. 
Magnified 150 times. A. Alveolar stroma containing many round and spindle 
cells; p. Pigment granules of melanin. 



(vii) Melanotic Sarcoma 

Melanotic sarcoma of the palate may occur as a downward exten- 
sion from a melanotic sarcoma of the choroid coat of the eye. The 
rarest of all forms of sarcoma, it is extremely malignant, becoming 
rapidly disseminated in the lungs and other organs. 



34° THE ORAL TISSUES 

It generally consists of small round cells which contain pigment 
granules. Pigment also exists in the intercellular substance. 

(viii) Endothelioma 

May occur in the buccal cavity, but is very rare. It represents 
a sub-variety of the sarcomata, but differs from them both morpho- 
logically and histogenetically. 

Thus the term includes all neoplasms which take their origin in 
endothelial cells, either those of the blood-vessels of the lymphatic 
spaces or the lymphatic vessels. It is easy to confuse them with 
the carcinomata, which in many ways they very closely simulate. 

The endotheliomata found in the gum most probably originate 
in the walls of the blood or lymphatic system. 

HISTOLOGY 

The bulk of the growth consists of cells, often arranged in alveoli, 
like the alveolar sarcomata, columns of endothelial cells — round, 
flat, or cubical in shape — which unite in an irregular fashion with 
each other, and nests of epitheloid cells. A fair amount of stroma 
of connective-tissue fibres is present between the cells of the alveoli. 

II. TUMOURS OF THE COMPLEX CONNECTIVE TISSUE TYPE 

(ix) Papilloma of the Gum 

GENERAL CHARACTERISTICS 

Definition. — An innocent tumour of papilliform character confined 
to the mucous membrane. 

Pathology. — This neoplasm belongs to a papillary type of growth 
assuming the morphological characteristics of villous excrescences 
and projecting, as a compound nodular mass above the surface of the 
gum or mucous membrane of the palate. It is closely related to the 
condylomata, verruca, and villous growths of the urinary bladder, 
rectum, larynx or trachea. 

The papillomata vary in size and shape, but often appear pe- 
dunculated, and have a tuberous floral aspect. Dense in consist- 
ency, they are devoid of tactile or painful sensations, grow slowly, 
and possess all the signs and symptoms of benign tumours. 

Two varieties exist — hard and soft. Of these the hard variety 
is the only one found in the mouth. 



DISEASES OF THE GUMS AND JAWS 34I 

Etiology. — The cause is obscure; but probably long-continued 
localised irritation is an important factor. Embryonic influences 
are difficult to trace. 

HISTOLOGY 

The epithelium is of the stratified squamous variety. Very 
abundant, it consists of many layers, and presents various stages of 
corneous transformation. 




Fig. 307. — Papilloma of the palate. Stained with Ehrlich's acid hasmatoxylene. 

Magnified 45 times. 

In length, the longest papilla may vary from 1.8 mm. to 2 mm. 

The body of the growth consists of dense connective tissue fibres, 
of which the cell elements are similar to those of the gum. There 
is increase in size and alteration in shape of the ordinary papillae. 
The vascular supply is more abundant than usual, and the con- 



342 



THE ORAL TISSUES 



stituent cells and fibres of the part are of a coarser nature than 
normal. 

(x) Hemangioma of the Palate 

GENERAL CHARACTERISTICS 

Definition. — A tumour consisting of masses of blood-vessels. 
Varieties. — Included under the term angioma are: 
(i) Naevi or birth-marks. 

(ii) Plexiform angiomata, or cirsoid aneurysms, com- 
posed of newly formed vessels, 
(iii) Cavernous angiomata. 




Fig. 308. — Hemangioma of the palate. Stained with borax-carmine. Mag- 
nified 30 times, o.e. Oral epithelium; b. Connective tissue with blood- 
vessels. 

Of these, naevi may be found on the lips; the presence of plexi- 
form angiomata in the mouth has never been recorded; but cavernous 
tumours may occur. 

These are made up of communicating spaces filled with blood and 
separated by connective tissue in greater or less abundance. 

Etiology. — Their origin is unknown. 

HISTOLOGY 

A cavernous angioma — haemangioma — consist of numerous 
rounded or oval spaces enclosed in delicate walls of connective 



DISEASES OF THE GUMS AND JAWS 343 

tissue, and lined with endothelium. The spaces are filled with blood 
corpuscles, while imbedded in the thin branching connective tissue 
fibres outside are some escaped leucocytes and proliferated tissue 
cells. The vessels in places are thrombosed, and haemorrhages of 
varying degrees of magnitude take place. 

The surface is clothed with epithelium, which has undergone no 
change from a normal condition. 

The process of phagocytosis, induced, in some instances probably, 
by the death of the blood elements occasioned either by their escape 
into the surrounding tissues or stagnation in the spaces, has not been 
observed in any specimens under consideration. 

(xi) Osteoma 

t 

Definition. — A connective tissue homologous tumour arising only 
in connection with bone, and essentially differing from calcification or 
ossification of other tumours. Osteomata may be classified as cir- 
cumscribed or diffuse. The former are found in the mandible, etc., 
and the latter in the maxillary sinus. 

The tissue consists of hard cancellous bone (see Fig. 316). 
Haversian canals may or may not be present. Periosteum surrounds 
the new growth. 

III. EPITHELIAL TUMOURS 

(xii) Adenoma 

Definition. — A tumour of the type of epithelial or glandular tissue; 
benign; only arises from pre-existing glandular tissue. Adenomata 
do not secrete, and have no ducts. 

Varieties. — (i) Acinous, (ii) Tubular. The former are found, 
amongst other places, in the base of the tongue, the lip, the parotid: 
the latter in the antrum. 

HISTOLOGY 

Secondary Changes. — Cystic degeneration following on mucoid 
softening and fatty degeneration of the epithelium. 

Cylindrical epithelial cells with a nucleus in the centre of each, in 
groups, separated by connective tissue with blood-vessels. 

(xiii) Carcinoma 

Definition. — Carcinomata are malignant growths which consist of 
epithelial cells contained in an alveolar stroma, derived from pre- 
existing epithelium. 



344 THE ORAL TISSUES 

This important group of malignant tumours is anatomically 
divided into three classes: — 

i. Spheroidal-celled, — e.g., scirrhus, medullary. 

2. Squamous-celled, — epithelioma. 

3. Columnar or cylindrical-celled, — e.g., of the rectum, 
uterus, etc. 

Further sub-divisions, based on pathological and clinical principles, 
are made. 

Of these, however, only one form need demand the attention of 
the dental surgeon, viz., the squamous-celled genus known as the 
epitheliomata. 

These spring either from the skin of the lips or the mucous mem- 
brane of the mouth, which in Vol. I has been described as being 
covered principally by stratified squamous or "pavement" 
epithelium. 

Etiology. — Long-continued irritation of the mucous membrane 
of the gum or palate, due to the presence of sharp edges of carious 
teeth, rough surfaces or margins of ill-fitting dentures, etc. 

In the case already quoted on p. 268, the cause could, without 
hesitancy, be attributed to the irritation of the epithelial "rests" 
in the periodontal membrane due to septic infection from the pulp 
of a dead tooth. 

Pathology. — In its earliest phases of development a squamous- 
celled carcinoma is either a small superficial indurated nodule on, 
or a fissure in the gum. It very rapidly becomes ulcerated, and then 
there appears an excavation whose edges are raised, irregular in 
outline, everted, and hard in consistency, whose base is indurated 
and irregular, whose environing structures are infiltrated with epi- 
thelial collections and small- celled masses. The lymphatics which 
drain the part, infect the lymphatic glands, which become enlarged 
and hard, and, later on, fixed to the surrounding tissues. 

Secondary Changes. — Ulceration of the surface. 

HISTOLOGY 

The substance of an epithelioma is composed of flat, round, 
or polygonal cells of varying size, arranged in alveoli, and imbedded 
in a connective-tissue stroma more or less rich in infiltrated cells. 

Two portions of the growth may be recognised and having dif 
ferent characters, clearly distinguished. 

In the younger developing part the cells are round and the stroma 



DISEASES OF THE GUMS AND JAWS 



345 





- 














ffffiBSfi . <jaa ' 




^P*« *»». -^ 




O E 

E 


i : . 

.' '■*:■■' 1 ■' I 






JPf "VjB 


■■''^.•'3lr-.'1 




w 

WJ , 

,t J? 




1M imMliB 

HP3v IP* ; '* 


ROT 






*4» « *i* 


.,;i 






f^i WPTJ 




f*L~ Vi • - /• ■■'■■ f^i 




• 'rrmjit' ■' ■■> 



Fig. 309. — Epithelioma of the palate. Prepared by fixing and hardening in 
alcohol and formalin. Magnified 45 times. Shows ulcerated surface, o.e. 
Oral epithelium; E. Columns of epithelium extending irregularly into the sub- 
mucous tissue. 



u E 







t 



E 



Fig. 310. — Another portion of the same. Shows the epithelial margin of 
the ulcer depicted in the previous figure. o.E. Oral epithelium; s. Submucous 
tissue. 



346 



THE ORAL TISSUES 



extremely cellular; in the older there is a tendency for the epithelial 
cells to become flattened and to display in places corneous or kera- 
tinous changes as in the superficial cells of the stratum corneum. 
Some cells show evidences of great activity in the shape of mitosis. 
The epithelial columns which have pierced the basement mem- 
brane and have invaded the sub-epithelial tissues are irregular in 
outline, generally being round or oval. They are discontinuous with 
the surface epithelium, and, cut off from the oral cells, become 
isolated and form alveoli or islands of epithelium separated by a 





Fig. 311. — Squamous-celled carcinoma of the palate. Prepared by har- 
dening in alcohol. Stained with haematoxylene. c. Cell nest. Magnified 50 
times. 



stroma which contains imperfectly developed connective tissue 
fibres and small-celled infiltration. 

In the epithelial prolongations into the sublying tissues and in the 
alveoli are often found collections of cell nests. 

Cell nests are concentrically arranged whorls of cells gathered 
around a homogeneous non-nucleated body or group of bodies which 
consist of keratinous material. This cornification progresses from 
within outwards, the change represented by the cells being crescentic, 
cubical and cylindrical respectively. 

Cell nests are only pathognomonic of epitheliomata when they 



DISEASES OF THE GUMS AND JAWS 



347 



are found in islands imbedded in the depth of the tissues far from 
the surface with which they are discontinuous. 

Some pathologists 1 believe that in the concentric bodies may be 
found most pronounced evidences of nuclear and protoplasmic 




c T 



Fig. 312. — A gumma of the mucous membrane of the palate. Stained with 
hasmatoxylene. Magnified 35 times, g.t. Granulation tissue on free surface; 
f. Fatty degeneration; c.t. Connective tissue of the palate, b. Blood-vessel 
cut longitudinally. 

necroses, "together with the peculiar process of inclusion of one 
epithelial cell by another, and an active invasion of leucocytes, some 
of which are degenerated and others apparently engaged as 
scavengers to devour the detritus resulting from the necrotic 
processes." 

1 Hektoen and Riesman. "A Text-Book of Pathology," Vol. I., p. 218, 1001. 



348 



THE ORAL TISSUES 



Syphilis 

This disease may affect the gums and buccal cavity in one of 
several ways. 

Hard chancres of the lips are far from uncommon: and it is possible 
for these primary sores to occur also on the tongue and gums. 




Fig. 313. — The same as the preceding. Lettering as before. Magnified 50 

times. 



A syphilitic stomatitis often develops in the secondary and ter- 
tiary stages of the infection, and gummata may be seen occasionally. 

The accompanying photomicrographs show gummatous infil- 
tration of the mucous membrane of the palate. 

A gumma is a chronic inflammation which leads to the production 
of granulation tissue. Varying in size, these lesions, as is seen in 
Fig. 313, are intimately associated with the surrounding tissues. 



DISEASES OF THE GUMS AND JAWS 349 

They may become absorbed; or remain in situ indefinitely without 
any signs of retrogressive changes; but they often caseate, break 
down, and form a deep punched-out ulcer. 

A gumma consists of a degenerated central part, an intermediate 
zone of small-celled infiltration, and a peripheral tract or belt of 
rapidly developing blood-vessels ramifying in a cellular matrix. 
Fatty degenerative changes are most frequently observed, and, no 
doubt, are occasioned by the cutting off of the nutritive supply of the 
most central portions, through changes in the vessel walls, which 
induce either complete thrombosis or diminution in the calibre of 
the vessels. 



OF THE MUCOUS LINING OF THE MAXILLARY SINUS 

Inflammation of the mucous membrane of the antrum is similar 
to that of other soft tissues. Details need not be recapitulated. 
Suffice it to say that the ciliated epithelium becomes rapidly de- 
generated and completely disorganised. The cell infiltration is 
carried on to an enormous extent, the tissue greatly swollen and 
thickened, and if not suppurative, undergoes fatty and mucoid 
changes (see Fig. 314). 

Spheroidal-celled carcinoma may occur. The photo-micrographs 
are from specimens given to the author by Sir Francis Farmer. 
Its chief characteristics are the following: — The cells are spheroidal 
in shape, and are exceedingly liable to undergo fatty degeneration; 
they are grouped into large soft alveoli; the separating stroma is 
very variable in amount, and, when scanty, is devoid of contractile 
properties. Medullary carcinomata are noted for their abundant 
vascular supply, in consequence of which haemorrhages are very 
frequent in the substance of the growth. 

c 

OF THE JAWS 

The external and internal plates of the alveolar processes of the 
jaws may, at times, be subject to the formation of osseous growths 
commonly, though not always correctly, spoken of as exostoses. 

Etiology. — Exostoses are very often regarded in the light of 
tumours, i.e., non-inflammatory growths. But many of the hard 
nodular periosteal swellings of the jaws may be considered with 



35° 



THE ORAL TISSUES 



E T 




Fig. 314. — Chronic inflammation of the mucosa of the antrum of Highmore. 
Magnified 230 times. E. Ciliated epithelium; et. Sub-epithelial tissue Jn- 
filtrated with inflammatory cells and products. {From a specimen given to the 
Author by Dr. Cidhberl Lockyer.) 




I 



lV;f 



" -V ; 




Fig. 315.— Hard spheroidal-celled carcinoma of the mucosa of the antrum of 
Highmore. Magnified 230 times. 



DISEASES OF THE GUMS AND JAWS 



351 



equal satisfaction as originating in the form of inflammatory osteo- 
phytes or hyperostoses comparable to osteitis in other parts of the 
body. Thus a distinction should be made between circumscribed 
osteomata and exostoses. When occurring in the mandible the 
former most likely are due to certain rare developmental anoma- 
lies of Meckel's cartilage; when elsewhere, the latter probably 
arise either from the periosteum of the jaws or of the teeth. In the 




M 



Fig. 316. — Endosteal osteoma of the mandible. Stained with haematoxylene. 
Magnified 150 times, b. Bone; M. Degenerated medullary tissue. 

first instance, exostoses may be due to a localised periosteal depo- 
sition of new bone analogous to the nodes produced by syphilis, 
often observed on the surface of the tibiae, or, as Turner believes, 
the outcome of "pyorrhoea alveolaris." 

Pathology. — Bony tumours generally appear as sessile swellings 
of a dense hard character, covered with thin mucous membrane 
which has a normal aspect. They are painless, slowly growing 
tumours, and generally easily diagnosed. 



352 



THE ORAL TISSUES 



HISTOLOGY 



The microscopical structure is interesting. An external shell or 
crust of compact covers a circumscribed nodule of cancellous bone, 
which simulates very exactly the normal types of osseous tissue. 



Tumours 

The tumours most frequently associated with the maxilla and 
mandible are cystic or solid. The former comprise dental cysts, 
epithelial and follicular odontomes, and mucous retention cysts (ade- 




%#3t ? 



Fig. 317. — Adenoma of the maxillary sinus arising from the periodontal mem- 
brane of a third maxillary molar. Stained with hsmatoxylene. Magnified 45 
times, d. Dentine; A. Adenoma; s. Soft tissue attached to the root of the 
tooth. 

nomata) of the antrum, & c. ; the latter, growths having the structure 
of fibrous tissue, mucous tissue, cartilage (enchondromata) and bone 
(osteomata and diffused and general diffused hyperostoses). Sar- 
comata and carcinomata, too, unfortunately, are far from 
uncommon. 

It is unnecessary to enter into further details of these various 
new formations, but brief reference to one of them may be mentioned. 



DISEASES OF THE GUMS AND JAWS 

Cvstic Adenoma of the Antrum 



353 



Cystic degeneration of an adenoma of the antrum of the left 
superior maxilla, occurring in a woman aged twenty-five is illustrated 
in Figs. 317 and 318. It had been occasioned entirely by the malpo- 
sition and fruitless efforte at eruption of the third molar. The peri- 
odontal membrane of this tooth had stimulated the mucous antral 








K \ 




av 






MM i7 




Fig. 318. — Cystic degeneration of the adenoma of preceding figure. Stained 
with haematoxylene and eosine. Magnified 250 times, e. Glandular epithe- 
lium; C. Cyst filled with albuminoid material; s. Stroma of tumour. 

glands to enlarge. The adenoma filled up the greater portion of 
the upper part of the antrum. In places the bony wall had become 
absorbed and the new growth extended through the soft tissues and 
mucous membrane of the palate in the neighbourhood of the molars. 
In breaking down, a deep punched-out ulcer was produced, which 
closely resembled a breaking down syphilitic gumma, or an 
epithelioma. 
23 



CHAPTER XIV 
DISEASES OF THE ORAL MUCOUS MEMBRANE 

Microscopical Elements in: (i) Inflammation; (ii) Tubercu- 
losis; (iii) Malignant degeneration. 



Stomatitis 

Definition. — Inflammation of the mucous membrane of the oral 
cavity, including that of the lips, cheeks and alveolar process collect- 
ively or severally. 

Differential Diagnosis 



Variety 



Causes 



Symptoms 



Diagnosis 



Terminations or 
complications 



I. Simple 

catarrhal 



(i) Local: Faulty 
oral hygiene, tar- 
tar, use of vul- 
canite dentures, 
mouth breathing, 

chemical irritants, 
abuse of tobacco, 
etc. 

(ii) General: Dys- 
pepsia, gastritis, 
gastric ulcer.gout, 
diabetes, chronic 
nephritis, infec- 
tious fevers, iod- 
ism, etc. 



Mucous mem- 

brane swollen, 
epithelium thick- 
ened, anorexia, 
fcetid breath, etc. 
Much mucous se- 
cretion. 



Favourable. 



Formation of vesi- 
2. Herpetic Catarrh and dys- cles which soon 
pepsia. rupture and leave 

scabs. 



Mouth dry. Re- 
moval of epithe- Quickly subsides. 
Hum accompan- 
ied with pain and 
haemorrhage. 



3. Aphthous Oidium albicans. 



Curdy, easily-de- Mouth always May be fatal 

tached, white moist, epithelium through diarrhcea 
patches. easily peeled off. j and septic ab- 

sorption. 



4. Ulcerative Dyspepsia, local Grey sloughs, foul' 
irritation, defec- breath, gums red 
tive oral hygiene, and swollen. 



Favourable. 



5. Syphilitic Secondary and Symmetrical: con- 
Tertiary. ; dylomata and 
mucous tubercles, 
gummata. 



6. Mercurial 


Abuse of mercury. 


Foul breath, swol- Gangrenous ulcer- 






len gums and 


ation; extensive 






tongue, profuse 


destruction of 






salivation, swell- 


tissues, and per- 






ing of parotid 


haps necrosis of 






and submaxillary 


bone. 






glands. Loosen- 








ing of teeth. 




7. Gangrenous 


Capillary throm- 


Foul breath, great 


Toxaemia, septi- 


or Cancrum 


bosis in cheek. 


tenderness of 


caemia, bronchi- 


oris 


perhaps due to 


parts, black in- 




tis and pneu- 




Lingard's bacil- 


durated slough 




monia. 




lus. 


on cheek, exten- 
sive sloughing. 







354 



DISEASES OF THE ORAL MUCOUS MEMBRANE 



355 



Varieties. — Herpetic, aphthous, catarrhal, syphilitic, ulcerative, 
mercurial, and gangrenous. 



HISTOLOGY 



The pathological changes occurring in the tissues are similar in 
all respects to those observed elsewhere. They do not require a 
special description. 



o E 










'if f 



Fig. 319. — Tubercular nodule in mucous membrane of cheek. Stained with 
hasmatoxylene and eosine. Magnified 250 times, o.e. Oral epithelium; G. 
Giant cells; e. Epitheloid and round cells; b. Blood-vessel. 

Tuberculosis 

Tuberculosis occurring in the mouth is at times of primary origin. 
More often, however, it follows laryngeal or pulmonary tuberculosis. 

Situation. — It is seen most frequently on the dorsum near the 
tip of the tongue, on the soft palate, on the mucous membrane of 
the cheeks and on the surface of the tonsils. 



356 THE ORAL TISSUES 

Origin. — It begins as a small superficial nodule, and soon breaks 
down and produces an irregular ulcer with infiltrated edges. 

HISTOLOGY 

A typical tubercle consists of many newly developed cellular 
elements. In its centre are found: (i) giant cells, two or more in 
number, consisting of granular cytoplasm with many peripherally- 
arranged nuclei. In and around these cells the Bacillus tuberculosis 
can be demonstrated by special staining. Surrounding the giant 
cells are (ii) numerous endothelial cells — oval, mononuclear bodies 
about io/x to 15/x in diameter, (iii) External to these are many 
round cells similar to lymphocytes from which they are probably 
derived. 

The accompanying photomicrograph may be considered to be 
fairly representative of the ordinary type of tubercular nodule 
found in the mucous membrane on the surface of the voluntary 
muscle fibres of the cheek. (Fig. 319). 

MALIGNANT DEGENERATION 
INTRODUCTORY 

Possessing no ordinary degree of practical utility, or of interest, 
for the modern dental surgeon as does a study of the degenerative 
conditions which may affect the root membrane of the teeth of 
man — one of which formed the subject of Chapter XII — it will 
doubtless be readily conceded that a condition which must engage 
the attention of the dermatologist and oral surgeon, as well as 
of the general student of this volume, is of necessity, and by vir- 
tue of its larger bearing on surgery and on the principles of life and 
death, far profounder in its importance and vaster in its clinical 
and pathological significance. Such an one is that type of degen- 
eration about to be described. 

The former — fibroid degeneration of the periodontal membrane — 
having a mesodermic derivation, is a local manifestation of a be- 
nign condition which, per se, remains always benign; the latter, 
ectodermic in origin, a local manifestation of a benign condition 
which, as will be presently seen, may become malignant: the first 
a product and an accompaniment of senility; the second, of youth or 
middle age; the one a common termination of a common affection, 
the other an unusual termination of a constantly occurring neoplasm. 



DISEASES OF THE ORAL MUCOUS MEMBRANE 357 

A similar type of degeneration, it is perfectly safe to say, has hitherto 
never been described as affecting the mouth and its contents. 

The mucous membrane of the oral cavity is usually very tolerant 
of the conditions to which it is subject as a consequence of injury 
by friction from foreign bodies placed upon it. It may, however, 
become pathologically affected and present a mottled appearance, 
or be covered by areas of tissue which look like dried blood-clot. 
Areas may remain for years unchanged, or if inflamed, may 
break down and ulcerate or undergo malignant changes. Such 
conditions should always be regarded with suspicion, and diagnoses 
made between dental, dyspeptic, tubercular and malignant 
ulcerations. 

A precancerous condition as observed on the surface of a pedun- 
culated fibroma may now be described. 

HISTOLOGY 

It will be convenient, in the first place, in detailing the minute 
anatomical appearances, which to the pathologist cannot fail to be 
of the greatest interest, to use the somewhat arbitrary, artificial 
divisions adopted by microscopists of the present day, as applied 
to the epidermal covering of the skin and certain mucous mem- 
branes of the body. The histo-pathology may therefore be con- 
sidered under the headings of — 

(i) Changes in the stratum corneum including the stratum lucidum 
and the stratum granulosum; 

(ii) Changes in the stratum mucosum; 

(iii) Changes in the sub-epithelial tissue or the cutis vera. 

(i) Changes in the Stratum Corneum 

The stratum' corneum extends over four-fifths of the periphery 
of the growth; where deficient, there is no differentiation of squamous 
stratified and columnar cells. But this layer presents many de- 
partures from the normal type. In some places it and the contiguous 
strata are insensibly merged into one another; in others, the former 
is sharply defined (Fig. 320), and then shows as an unusually thin 
band of flat, narrow, stratified corneous cells with elongated planary 
nuclei whose karyoplasm is indistinguishable and structureless. 
There is a marked tendency, here and there, toward desquamation; 
and the free surface is partially covered with layers of keratin or 



358 



THE ORAL TISSUES 



kerato-hyalin material, which presents either as a mass of tiny 
granules or a denser, more homogeneous, partially detached, ground- 
glass-like matrix. Polychrome methylene blue rendered the con- 
tents of these cells and those of the stratum granulosum very 
prominent, and accentuated, by means of its chemical affinities, the 
presence, in places, of flakes of eleiden, (Ranvier) or kerato-hyaline. 
Fig. 322 shows that in places these superficial layers penetrate almost 
to the corium of the fibroma. 



s c 




Fig. 320. — Degenerated epithelium on surface of fibroma. Stained with poly- 
chrome methylene blue and eosine. s.c. Line of demarcation between superficial" 
strata and stratum mucosum; d. Ballooned cells containing kerato-hyaline; e. 
Epithelial cells of a less degenerate type; c. Connective tissue fibres and cells com- 
prising the substance of the fibroma; 1. P. Normal character of interpapillary 
process of dermis. Magnified 60 diameters. 



Particularly striking are irregularly arranged patches of these 
degenerated cells; they appeared in every section. The cell wall 
had apparently become grossly distended (ballooning) by retrogres- 
sive changes occurring within it (Figs. 321 and 324). The nuclei 
in many cases are absolutely destroyed; the spongioplasm had 
disappeared, and the hyaloplasm, which in normal young cells 
constitutes the greater relative amount of the protoplasm, had 
evidently become converted into masses of keratinized material 
which in vertical sections of the epithelium often filled the whole 
of the ballooned cell and often produced a meniscus-like body, the 
open space of which was invariably situated at the peripheral portion 



DISEASES OF THE ORAL MUCOUS MEMBRANE 



359 



of the cell, and sometimes was empty but at others partially filled 
with granular detritus (Fig. 321). These patches extend some 
distance toward the centre of the fibroma (Figs. 325 and 326); 
and the epidermal cells were simultaneously proliferating inward. 

(ii) Changes in the Stratum Mucosum 

A little lower down, and nearer to the rete mucosum or Malpighii, 
the cells are more normal in shape and size. The greater number 




Fig. 321. — To show minuter details of epithelium stained as in preceding, k. 
Meniscus of kerato-hyaline material; g. Granular type of kerato-hyaline material 
on free surface; N. Nucleus lying in a clear space; s. Inter-epithelial space devoid 
of "prickles." Magnified 240 times. 

are "prickle" cells; but many have no intercellular bridges and 
are not separated by interepithelial channels. The majority of the 
"prickle" cells exhibit their nuclei lying in a clear, narrow space 
(Fig. 321). Perhaps the greatest interest centres in these nuclei. 
All changes and rearrangements in their karyoplasm can be noticed. 
The majority show them in a "resting" stage, but the chromosomes 



3 6 ° 



THE ORAL TISSUES 



while large in size seem very few in number — a condition known as 
hypo-chromatosis. On the other hand, many of the changes due 
to the process of mitosis are observed and the figures well exhibited 
in the hsematoxylene-stained sections. Those treated by the Van 
Gieson method are not so brilliant. 

Most of the changes familiar to the histologist and pathologist 
can be detected. Thus, typical heterotype amphiasters, ring 
chromosomes and centrosomes, and many instances of asymmetric 




Fig. 322. — Same as preceding, staining and magnification similar. K. 
Kerato-hyaline matrix; s.c. Superficial degenerated stratum of cells; s.c. Stratum 
mucosum (degenerated). 

mitoses occur. There are slight evidences of karyoclasis and karyo- 
lysis, but no vacuolation of the nuclei, though the cells themselves 
are certainly, generally speaking, undergoing hydropic degeneration. 1 
Darier's "coccidia" and typical myeloid cells are also present, but 
not frequent — at least bodies resembling them appear to exist 
scattered about in places. 

Equally important with the above metamorphoses are the presence 
of the typical cell-nests of the squamous carcinomata. A few are 

1 Delafield and Prudden, Pathology, igoi. 



DISEASES OF THE ORAL MUCOUS MEMBRANE 



361 



discerned near the deepest portion of the rete mucosum, and are 
unduly large, and form, as seen in Fig. 327, a striking feature of the 
sections. 

The delicate basement membrane which supports the rete 
Malpighii is, generally speaking, extremely irregular in outline 
(Figs. 328 and 329). The columnar epithelial cells situated upon it 




s c 



S G 



Fig. 323. — Surface of fibroma. Stained with haematoxylene and eosine. s.c. 
Superficial strata of a fairly normal character; s.G. Stratum mucosum with 
oedematous epithelium; P. Epithelial cells proliferating inward, and breaking 
through the normal basement membrane; f. Connective tissue of fibroma; s. 
Small round-celled infiltration. Magnified 50 diameters. 

appear to be fairly regular in shape, and to show few evidences of 
degeneration or oedema. But the uniformity of outline of the base- 
ment membrane repeatedly and greatly departs from its usual 
foldings, and the interpapillary spaces are exceedingly irregular. 

In that portion of the periphery of the growth where the strata 
corneum, lucidum, and granulosum are absent, the epithelial cells 
are all more or less oedematous (Fig. 329), and, briefly, exhibit signs 
of a condition corresponding to eczema of the skin. They are 



362 



THE ORAL TISSUES 



swollen, rounded, greatly multiplied, and tend to an anomalous 
degeneration, being absolutely devoid of intercellular bridges. As 
a result of the colliquative degeneration, vesiculation has slightly 
occurred; and there are also many migratory cells, etc. Their 
depth from the surface does not modify these changes (Fig. 330). 
The process of mitosis is with difficulty made out in these situations, 
though there is no doubt that it is taking place, and that some 
proliferation and growth of the epidermis accompanies it. 




Fig. 324. — Large patches of ballooned epithelium in degenerated oedematous 
tissue. Stained with haematoxylene. Magnified 250 diameters. 



(iii) Changes in the Cutis Vera 

Here the papillae are seen to be, in parts of the fibroma, very 
irregular, as already indicated. A noticeable condition is, however, 
the small round-celled infiltration which has been associated with 
the cytological metamorphoses. In the neighbourhood of the cell 
nests, in the most irregularly shaped interpapillary processes, and 
beneath the oedematous surface this infiltration is most marked. 
The cells themselves are largely of the Unna's plasma-cell type, 
mixed with a few leucocytes (polymorpho-nuclear neutrophils 



DISEASES OF THE ORAL MUCOUS MEMBRANE 



3 6 3 




Fig. 325. — Another degenerated patch showing its superficial position; 
stained with haematoxylene. d. Cluster of ballooned cells; e. Irregular outline 
of basal layer of epithelium. Magnified 45 diameters. 




Fig. 326. — Similar to preceding, but exhibiting the various stages in the process 
of formation of the ballooning of the cells. Stained with haematoxylene and eosine. 
D. Cells of a fairly normal character, but passing, on the left, to the condition 
which is at its highest point of development at k; e. Epithelium of stratum 
mucosum. Magnified 50 diameters. 



3 6 4 



THE ORAL TISSUES 



and lymphocytes) and some eosinophiles and connective tissue 
nuclei and the "mast cells" of Ehrlich. In addition there is an 
abundant blood supply. 



ETIOLOGY 



It is now permissible, necessary, and logically sequential that an 
inquiry should be instituted with regard to the theory concerned 




Fig. 327. — Cell nest at base of epithelial column. Stained with hsmatoxylene 
and eosine. E. Epithelium of stratum mucosum; E.C. Cell nest showing corneous 
character of the central portion; K. Epithelial cells undergoing mitosis; nuclei 
displaying asymmetric mitoses; L. Polymorpho-nuclear leucocyte in small-celled 
infiltration. Magnified 250 diameters. 

in the causation of the changes already described, and an endeavour 
made to bring them into line with those of modern research. It 
may, however, be stated at the outset that many difficulties beset 
this work. The recording of clinical histories and the describing of 
macroscopical and microscopical anatomy are accomplished with 
facility and some degree of certainty; not so when attempts at 
etiology are undertaken. 

The exciting cause (or causes) of cancer has for generations per- 



DISEASES OF THE ORAL MUCOUS MEMBRANE 



365 



plexed the minds of men, and today there is probably no one de- 
partment of medical science which has more strenuous followers, 
bacteriology and therapeutics not excepted. It would not be germane 
to the scope and intention of this chapter if the various questions 
relative to it were discussed. It must be sufficient if allusion is 
very briefly made to the latest opinions of authoritative and com- 
petent witnesses, and these suggestions applied to the present case. 




Fig. 328. — Irregularity of epithelial surface. Stained with hasmatoxylene and 
eosine. e. Epithelium; f. Tissue of fibroma. Magnified 45 diameters. 

The clinical notes do not in any way account for the presumably 
sudden assumption on the part of an innocent tumour of malignancy. 

Physical and chemical lesions seem to be at once eliminated as 
affording the least possible clue. There was no apparent source of 
irritation or traumatism as occurs unmistakably in mammary 
scirrhous carcinoma, or labial epithelioma, or "chimneysweep's" 
cancer, and the predisposing factor of age can also be put out of court. 
Sections were stained specially to discover if bacterial or protozoan 
or blastomycetic infection had occurred — with negative results; 



3 66 



THE ORAL TISSUES 



although it is most obvious that the skin and mucous membranes 
generally must be easily subject to invasion by the micro-organisms 
which they so constantly harbour. 




Fig. 329. — Surface of fibroma at junction of eczema-like epithelium, with the 
epithelial layers of preceding sections, s. Epithelium similar to that in preceding 
figure; e. (Edematous cells with no superficial strata, and extending in irregular 
columnar formation into the substance of the fibroma. The rapidly growing 
epithelium and the round-celled infiltration of the sub-epithelial tissue are shown. 
Magnified 45 times. 



Serious and continuous consideration of the clinical history, com- 
bined with the patho-histology, would seem to argue against Cohn- 
heim's embryonal theory, which was originally introduced in 1882, 
and has been recently revived by Sir Henry Morris, who, in the Brad- 
shaw Lecture of the Royal College of Surgeons of England, in 1903, 



DISEASES OF THE ORAL MUCOUS MEMBRANE 



367 



strongly advocated the views therein promulgated. The mechanical 
isolation hypothesis of Ribbert, as well as the anaplasic theory of 
Hausemann 1 would also appear to fall to the ground. 

But there is apparently nothing to refute, nor, be it remarked, to 
absolutely verify, the quarter-of-a-century-old doctrines of Thiersch 
and Waldeyer, who believe that cancer cells take their origin from 
altered pre-existing epithelial cells. 




Fig. 330. — Dense cell infiltration of dermal tissue at base of epithelial column. 
E. Stratum mucosum; R. Cellular infiltration in connective tissue. Magnified 
210 times. 



In a most instructive paper presented to the Royal Society of 
London, in December 1903, by Messrs. Bretland Farmer, Moore, 
and Walker, entitled "On the Resemblances Exhibited Between the 
Cells of Malignant Growths in Man and Those of Normal Repro- 
ductive Tissues," the following sentence occurs : " In a typical example 

1 See Bashford and Murray, "The Significance of the Zoological Distribu- 
tion, the Nature of the Mitoses, and the Transmissibility of Cancer," Proceed- 
ings of the Royal Society, vol. lxxiii, 1904. 



368 THE ORAL TISSUES 

of rapidly growing epithelioma it is seen that in the early stages of 
the proliferation of the Malpighian layer, the cells of the invading 
tissue at first pass through a cycle of somatic divisions, exactly as in 
the early stage of reproduction tissue. The resemblance may extend 
to the frequent production of giant cells, a common occurrence in 
each case. As cell multiplication proceeds, however, a change passes 
over the cells themselves. The protoplasmic continuity, to which 
the "prickly" character is due, becomes more or less obliterated, 
and the cells assume that appearance of indifferent germ tissue so 
well known as a feature of the elements of which malignant growths 
are largely made up." 

The conclusions to which these observers came were that malig- 
nant new-growths are really nothing more nor less than "reproduc- 
tive (gametogenic) tissue arising in abnormal situations and pos- 
sessed of an independence and power of growth like that of the testis 
in the mammalian body". 

The occurrence of the phenomena described by them was cor- 
roborated, in the case of the lower vertebrates, by Bashford and 
Murray, in January, 1904. 

To sum up. It may be said that if an explanation were insisted 
upon for the causation of this disease, the opinions held by Calcott 
Fox and MacLeod in "A Case of Paget's Disease of the Umbilicus," 
appearing in the British Journal of Dermatology, vol. xvi, No. 2, 1904, 
taken in conjunction with the so-called "autotoxic hypothesis," 
might in all probability throw some light on the subject. 

The former writers remark, "It has never been demonstrated, 
and it seems highly improbable, that the degenerated cells which 
occur in the epidermis or the epithelium in Paget's disease can take 
on malignant characters. It appears to us, however, more reason- 
able to assume that the malignant growth originates in epithelial or 
epidermal cells which, not having degenerated, have reverted and 
assumed a capacity for proliferation through the prolonged action of 
some cause which, acting most powerfully on undifferentiated cells, 
produces their degeneration, than in a matrix of cells which has 
been deposited there at some period more or less remote." The 
latter assume that "The products of perverted metabolism in animal 
organs or tissues produce morbid effects in the individual's body." 

In the present instance it is conceivable that the mechanical and 
physiological growth of the fibroma beneath and internal to its 
epidermal convering may have induced, in the course of time, the 
perverted metabolism above mentioned. Although the growth of 



DISEASES OF THE ORAL MUCOUS MEMBRANE 369 

the neoplasm was slow, it is entirely probable that it was only quite 
recently that the epithelium had undergone the carcinomatous 
changes. 

Sir James Paget, 1 who first drew attention in the St. Bartholo- 
mew's Hospital reports for 1874 to cases of a certain disease of the 
mammary areola?, has been followed by many other contributors to 
a general knowledge of the subject, among whom may be mentioned 
Butlin, 2 Wickham, 6 Darier, 4 Duhring, 3 Wile, 5 etc. It has, how- 
ever, only recently been found that the genitalia may, at times, 
undergo similar morbid changes, histories having been put on 
record by Pick, Rolleston, 7 Dubreuilh, 9 Ravogli, 8 and others, 
including Fordyce, in 1903, at the New York Dermatological Society; 
While Calcott Fox and Macleod (loc.cit.) have reported one instance of 
Paget's disease of the umbilicus. 

The definition of "malignant papillary dermatitis" has been 
applied to this affection; and it constitutes, in the words of MacLeod 
("A Practical Handbook of the Pathology of the Skin," 1903), 
"a peculiar type of persistent dermatitis which clinically in its early 

stages somewhat resembles chronic eczema In later stages of 

the disease its malignant character becomes evident, and a carcinoma 
develops." 

CONCLUSIONS 

The signification and direct bearing on practical dental and oral 
surgery of malignant disease of the gums is immediately important 
and clear. That certain of the innocent neoplasms of the fully 
formed connective tissue type may undergo secondary malignant 
changes is a well-known fact in pathology. Thus, lipomata may 
become sarcomatous, and papillomata and verrucae carcinomatous. 
Fibromata usually are subject, if they degenerate or become altered 
in structure, to calcification and mucoid softening, or ulceration 

1 'Disease of the Mammary Areola Preceding Cancer of the Mammary 
Gland." St. Bartholomew's Hospital reports, 1874. 

2 Medico-Chiriirgical Transactions, 1876. 

3 American Journal of the Medical Sciences, 1883. 

4 Complcs rendus, Societe dc Biologie, 1889. 

6 American Journal of the Medical Sciences, 1884. 

6 International Congress of Dermatology, Paris, 1889. 

''Pathological Society Transactions, 1897. 

8 International Medical Congress, Rome, 1894. 

9 British Journal of Dermatology, 1901. 

24 



37° THE ORAL TISSUES 

when placed on exposed surfaces. It was, probably, a mere accident 
in the present instance that a fibroma should bear on its periphery 
signs of malignancy. Epithelia, especially of the pavement or 
squamous type, are particularly prone to proliferate, and it is a 
matter of great surprise that the oral epithelium does not oftener 
produce carcinomata. 

The epithelium of the mucous membrane of the cheek would 
almost seem to possess a large measure of immunity from it. Here 
there is apparently a frequent source of irritation and tissue change; 
and yet cheek carcinomata are most uncommon. The surface of lip, 
tongue, and palate are, however, favourite sites. 

The extreme rarity of malignant disease of the gums must not be 
taken too literally; it may be commoner than is supposed, for it is 
impossible to say how many fibromata have been excised which 
were already undergoing these degenerations but which remained un- 
recognised inasmuch as no microscopical examination had been made. 

From the point of view of the frequency of its occurrence it might, 
perhaps, occupy a position intermediate between that of the cheeks 
and the other structures named. As the removal of a diseased 
periodontal membrane will often obviate the formation and develop- 
ment of a dental cyst, or even perhaps sarcoma or epithelioma of the 
jaws, so too the removal of what is considered to be merely an 
"ordinary epulis" may prevent the onset of Paget's disease. Extir- 
pation may really signify prevention of its inception. 



CHAPTER XV 

ODONTOMES AND ODONTOCELES 

Microscopical Elements in: — (i) Epithelial odontomes; (ii) Follicular 
odontomes; (iii) Radicular and (iv) Composite odontomes; (v) Sub- 
capsular odontoceles; (vi) Extra-capsular odontoceles. 

Definition. — "A tumour composed of dental tissues in varying 
proportion and different degrees of development arising from tooth 
germs or teeth still in the process of growth" — (Sir John Bland- 
Sutton). "An odontome is a tumour derived from the special cells 
concerned in tooth development It is a mass of new forma- 
tion which tends to grow or persist, fulfils no physiological function, 
and has no typical termination; it also fulfils Thoma's definition of a 
tumour being 'an autonomous or independent new growth,' the 
law laid down by him that 'it reproduces with more or less deviation 
the structure of the part from which it primarily arises." ("The 
Report on Odontomes," London, 1914.) 

Classification. — According to Sir John Bland-Sutton, 1 these 
tumours may be grouped as follows: — 

(A) Aberrations of the enamel organ: — 

1. Epithelial odontomes. 

2. Calcified epithelial odontomes. 

(B) Aberrations of the follicle (capsule) : — 

1. Follicular cysts. 

2. Fibrous odontomes. 

3. Cemen tomes. 

(C) Aberrations of the dental papilla: — 
1. Radicular odontomes. 

(i) Dentomata. 
(ii) Osteo-dentomata. 
(iii) Cementomes. 

(D) Aberrations of the whole tooth germ: — 
Composite odontomes. 

(E) Anomalous odontomes. (Compound follicular odon- 
tomes.) 

1 Trans. Odonto. Soc, Nov. 1887. 
37i 



37 2 THE ORAL TISSUES 

This classification has been revised (1914) by a committee com- 
posed of Messrs. Douglas Gabell, W. Warwick James, and J. Lewin 
Payne, and is as follows: — 

1. Epithelial odontomes (where the abnormal development 
occurs in the dental epithelium only) : — 

1. Multilocular cysts. 

2. Dentigerous cysts. 

3. Dental cysts. 

2. Composite odontomes (where the abnormal development takes 
place primarily in the dental epithelium, and secondarily in the 
dental papilla, and may occur in the follicle (capsule) also) : — 

1. Complex composite odontome. 

2. Compound composite odontomes. 

3. Geminated composite odontomes. 

4. Gestant composite odontomes, in which a denticle 
is contained within, or surrounded by, the walls of a 
tooth, called by Arkovy " odontoma internum liberum. " 

5. Enamel nodules. 

6. Dilated composite odontomes. 

3. Connective-tissue odontomes (where the abnormal develop- 
ment takes place in the dental tissues of mesodermic origin alone) : — 

1. Fibrous odontomes. 

2. Cementomes. 

Epithelial Odontomes 

Origin. — They may arise from abnormal growth of the epithelial 
"rests" found in (i) diverticula from enamel organs, or (ii) aborted 
tooth germs. 

Synonym. — "Multilocular cystic tumours." — (Eve). 

Macroscopical Appearances. — A soft mass containing cysts of 
various sizes lying between the external and internal alveolar 
plates which have become much attenuated and enlarged (Figs. 
331 and 332). A more or less completely formed tooth can generally 
be found in the neighbourhood of the growth. At times portions 
of the tumour may become ossified, columns of bony-like substance 
being embedded in its midst; or the whole growth may undergo 
osseous changes. Such cases have been described by Tomes and 
Miller. 



ODONTOMES AND ODONTOCELES 



373 




Fig. 331. Fig. 332. 

Fig. 331. — Lateral view of an epithelial odontome. Actual size. 
Fig. 332. — A superficial aspect of the same showing several cysts. 




Fig. 333.— A section through the thickest portion of the mass, showing the 
epithelial columns extending into the mesodermic tissue. Prepared by hardening 
in alcohol. Stained with hcematoxylene. Magnified 45 times, e. Epithelium; 
c. Connective tissue. 



374 



THE ORAL TISSUES 



HISTOLOGY 



The mass chiefly comprises bundles of connective tissue fibres, 
densely and closely packed; in places a round celled infiltration, 
which probably represents embryonic mesodermic tissue, can be 
observed. 




Fig. 334. — Similar to the preceding. Magnified 50 times, c. Early stages in 
the formation of a cyst; e, Epithelium. 



Greater interest, however, centres in the epithelium. This 
extends primarily in the form of solid rods or territories into the 
substance of the odontome. The epithelial columns anastomose 
and branch freely. In some situations they are extremely narrow, 
in others broad. Thus they vary in width from 0.6 mm. to 1.0 mm. 



ODONTOMES AND ODONTOCELES 



375 




Fig. 335. — Similar to the preceding. A longitudinal section through the 
entire wall of a small cyst, showing its contents, e. Epithelial tissue; c. Cyst 
contents; M. 



Mesodermic tissue. 




Fig. 336. — A portion of the wall of a cyst in an epithelial odontome. Pre- 
pared as the preceding, e. Epithelial cells; d. Degenerate cells; c. Colloid mate- 
rial which constitutes the cyst contents. 



376 THE ORAL TISSUES 

Islands of mesodermic fibrous tissue are often formed by the junction 
of the under side of the epithelial involutions. 

The cells here are very similar in constitution to those of the 
deepest layers of the oral epithelium. In shape they vary somewhat. 
Those at the margins of the ingrowths are small and closely packed 
together, each having nuclei, with pronounced chromatin granules 
and karvoplasm. They are cubical in shape. Those in the central 
portions of the mass are branched, and have elongated flattened 
nuclei, many of which contain nucleoli in addition to the karvoplasm. 
Many signs of rapid subdivision of the cells can be noted. In the 
centre of the earliest-formed islands the method of breaking down 
or dissolution of the cells, with the first commencement of cystic 
degeneration, can be easily studied. They assume a shrunken 
appearance, with hydropic nuclei. Joined by their processes, they 
bear a distant resemblance, as Bland-Sutton has suggested, to the 
stellate cells of the enamel organ. 

Follicular Odontomes or Dentigerous Cysts 

Origin. — An excessive amount of secretion of fluid between the 
enamel or Nasmyth's membrane and the dental capsule, which, 
accumulating, distends the space and produces a cyst. 

Synonym. — Dentigerous cyst. 

Contents. — A glairy fluid, with crystals of cholesterine and broken 
down epithelial cells in suspension, and a fully or partially developed 
tooth or teeth lying in its interior. 

They may be (i) Simple (containing one tooth) or (ii) Compound 
(containing many teeth). 

GENERAL CONSIDERATIONS 

Teeth found in these cysts usually possess no Nasmyth's mem- 
brane. The recognition of any new fact is likely to be succeeded 
by the advancement of some novel theory which may serve a useful 
end in attempting to explain what is otherwise inexplicable. Such 
is the difficulty of obtaining reliable, and therefore, scientific infor- 
mation on many obscure physiological and pathological processes, 
that occasionally the most commonplace and minor observation 
becomes the progenitor of a vast store of valuable knowledge. 

These generalisations apply equally to the various regions of the 
body, and to every organ or tissue which they contain or of which 



ODONTOMES AND ODONTOCELES 377 

they are constructed. If etiological or pathological processes were 
more frequently contemplated from the anatomical standpoint, there 
would be less confusion as to the manner of operation of morbid 
changes, and as to the successful and non-empirical treatment of 
diseased conditions. 

It would seem at first sight a somewhat trivial and unimportant 
matter that the retained teeth of dentigerous cysts may have no 
Nasmyth's membrane investing their coronal surfaces, or, indeed, 
any portion of them. But it is probably true. Some time ago 
the author removed from a dentigerous cyst a tooth so affected. 

In the mouth of a patient, a boy of nine and a half years, there 
existed a swelling in the neighbourhood of the left mandibular 
second deciduous molar. After operation, the second premolar 
was easily detached uninjured from the floor of the cavity on which 
it was lying horizontally. It was thereupon subjected to Paul's 
phloroglucin and nitric acid mixture, in order to ascertain if the 
enamel cuticle was intact or diseased. It was found to be entirely 
absent. 

The rarity of this form of cyst, or follicular odontome, according 
to Bland-Sutton, and the heretofore incorrect statements as to the 
nature of the membrane, have prevented much, if any, investigation 
of the subject. Although at present the author has been fortunate 
enough to obtain one specimen only, it is, however, extremely prob- 
able that it is the rule, that when dentigerous cysts occur there 
is concomitant absence or failure of development of Nasmyth's 
membrane. 

To what theories does this fact, then, give rise? 

The anatomical relationships of the parts around an unerupted 
tooth must be briefly recalled. Beginning from within, and passing 
outwards, the following structures meet the eye, and are placed in 
order, as — the external free surface of the enamel, the translucent 
pellicle of Nasmyth's membrane, its cellular layer, the internal 
layer of the dental capsule, and the external layer of the same. 

The cyst wall consists of "dense strands of longitudinally arranged 
connective-tissue fibres, which are thick and strong, but loose in 
texture nearest the bone; while gathered into bundles further in, 
composing the bulk of the cyst, are connective tissue fibres and cells, 

all freely supplied with blood-vessels Ultimately a fully 

developed dentigerous cyst is lined with a layer of epithelial cells, 
one or more deep." Like all cysts of new formation. Whence 
comes this layer of epithelium? It is probably identical with the 



378 THE ORAL TISSUES 

external epithelium of the enamel organ, which, on completion of 
development, becomes the cellular layer of Nasmyth's membrane. 
If this is the case, then the cyst contents are probably formed by the 
degeneration and liquefaction of the stellate reticulum. 

Inspection of a tooth germ at an early stage of growth, when cut 
in a vertical position, reveals the stellate reticulum of the enamel 
organ bounded externally by a layer of small round cells (external 
epithelium), internally by round or polygonal cells {stratum inter- 
medium), and cylindrical cells with prominent nuclei (internal 
epithelium or ameloblasts). The first-named, at one time, extends 
without interruption almost around the entire tooth germ. The 
actual date of its disappearance is unknown. It is clear, however, 
that that portion situated near the cusps or incisive edges of the 
teeth is the last to atrophy. 

Of all the structures in the enamel organ which could possibly 
originate the thick, glairy fluid which forms the contents of the 
cyst, the stellate reticulum is the one. As has been already mentioned 
the external epithelium probably remains as the internal lining of 
epithelial cells in the fully developed cyst wall. It has, in this 
instance, been modified as far as its functions have been concerned, 
and has never formed the cellular layer of the enamel cuticle, for 
that thin film has never existed. It is impossible to conceive that, 
had it been present, it had been destroyed by any pressure or 
chemical action on the part of the cyst contents. 

The internal epithelium cannot presumably take part in the 
degeneration. For its work is accomplished in the formation of the 
enamel, finally, in an atrophied or exhausted state, losing its cellular 
identity, and degenerating into the keratinous homogeneous pel- 
licular layer of the membrane. 

There remains, therefore, the stratum intermedium and the stellate 
cells. Of the former little is known concerning either its function 
or its real anatomical relationships. The author ventures, therefore, 
logically and reasonably to believe that it is the cells of the "packing 
material" which are the all-important factor. 

One argument against the acceptance of this view which might 
undoubtedly be raised is that the stellate reticulum disappears very 
early in the development of the tooth. This is true. But there 
can be no objection to the expression of the opinion that a portion 
of it may escape atrophy, and, remaining behind as an unabsorbed 
body, have its constituent cells suddenly undergoing centrifugal 
proliferation, with its inevitable termination of degeneration, death, 



ODONTOMES AND ODONTOCELES 379 

and liquefaction. The fluid thus produced would have no difficulty 
in surrounding the whole surface of the crown, and, if the roots 
were completed, enveloping the entire or greater part of the tooth. 

Still it is not easy to prove the anatomical origin of a dentigerous 
cyst in the light of present knowledge. Nevertheless, one or two 
considerations may be applied to its study. Thus: — 

(a) There is an analogy in the formation of epithelial odontomes, 
which are believed to arise from irregular diverticula from or un- 
atrophied remnants of the tooth band. 

(b) There is a further similarity between the microscopical 
appearances of the cells of an epithelial odontome which are about to 
break down and the cells of the stellate reticulum as Sir John Bland- 
Sutton 1 has already noticed ("Tumours Innocent and Malignant," 
4th edition, 1906), especially when they are becoming aged. 

(c) The teeth found in follicular odontomes are often only par- 
tially complete. This agrees with the fact that the stellate reticulum 
disappears early in the life-histories of teeth. 

(d) And, lastly, by a process of elimination it is satisfactory 
to surmise that no other constituent of the enamel organ could 
produce the cyst contents than these cells. 

These remarks are based on the assumption that some cells of 
the enamel organ play an important part in the genesis of a dentig- 
erous cyst. There is just, however, one other possibility if this 
suggestion is incorrect, and that is that the follicle itself may originate 
its own cyst. 

Sections of the dental capsule, when made at the time of its fullest 
growth, exhibit many winding tube-like bodies composed of epithe- 
lium, which run in an inward direction, and are almost exclusively 
confined to its inner border, i.e., the part which is contiguous with 
and closely applied to, Nasmyth's membrane. 

Now, it is possible, but unlikely, that proliferation and growth 
occur in one or more of these bodies. As these are placed externally 
to the external epithelium of the enamel organ, one would expect 
to find the enamel cuticle intact on the surface of the tooth embedded 
in the cyst. But this is not so. 

Hence it is that, taking all things into, consideration, and weighing 
carefully the pros and cons, the author ventures to express his belief 
in the origin of the cyst in the manner already detailed, — a belief 
confirmed by the fact that Messrs. W. A. Maggs and Pare also 

1 ".The central cells degenerate and give rise to tissue resembling the stellate 
reticulum of the enamel organ" — p. 228. 



3 8o 



THE ORAL TISSUES 




Fig. 337. — The mucous membrane and soft tissue external to the wall of a 
follicular odontome. Prepared by hardening in alcohol. Stained with Ehrlich's 
acid haematoxylene. Magnified 230 times, oe. Oral epithelium; c. Tissues of 
the gum; p. Periosteum; b. Attenuated bone. 




Fig. 338. — The wall of a follicular odontome. The innermost part of the 
section in Fig. 337. b. Attenuated bone; W. Wall of cyst; bv. Blood-vessels; 
f. Internal surface of wall. 



ODONTOMES AND ODONTOCELES 38 1 

noticed the absence of Nasmyth's membrane under similar condi- 
tions, and noted the anomaly in Guy's Hospital Gazette for 1904. 

Follicular odontomes are undoubtedly congenital or develop- 
mental in their origin. But a good deal of confusion still exists 
as to their pathogenesis. It is unnecessary to enter into the argu- 
ments of many writers. Let it therefore suffice to recall that, 
among the older ones, Broca believed that they arose within the 
tooth capsule, sac, or follicle, the enamel organ having disappeared 
"under morbid influences;" that Malassez explained that they 
were due to hypertrophy of epithelial rudiments of the enamel 
organ; that Albarran considered they were inaugurated by the 
proliferation of the aborted epithelium of the fibrous tissues normally 
present in the iter dentis; and that Salter ascribed to "a sort of 
epithelium" clothing the so-called enamel pulp "the power of 
assuming the function of secreting fluid." 

Bland-Sutton defines them thus: "Swellings [which are] often 
called dentigerous cysts, a term which has come to be used so very 
loosely that it should be discarded in the necessity for precision. 
They arise commonly in connection with teeth of the permanent set, 
and especially with the molars; sometimes they attain large dimen- 
sions and produce great deformity, especially when they arise in the 
upper jaws and happen to be bilateral. Rarely they occur in 
connection with supernumerary teeth. The wall represents an 

expanded tooth-capsule The cavity of the cyst usually 

contains viscid fluid and the crown or the root of an imperfectly 
developed tooth. Occasionally the tooth is loose in the capsule, 
sometimes inverted, and often its root is truncated; exceptionally 
the tooth is absent or represented by an ill-shaped denticle. The 
walls of the cyst always contain calcific or osseous matter; the 
amount varies considerably." 

Tomes and Nowell write: "The follicular cyst arises in con- 
nection with teeth retained in the jaws, generally premolars or 
molars. They cause great distension of the jaws" (p. 725); and, 
in accounting for their mode of formation and generation of the 
fluid contents, assert (p. 732): "When the development of the 
enamel is completed, its outer surface becomes perfectly detached 
from the investing soft tissue, and a small amount of transparent 
fluid not uncommonly collects in the interval so formed." 

It is a well-known fact that the deciduous and permanent teeth, 
when about to erupt, may present over their crowns a bluish, soft 
vesicle containing serum (eruption cysts). It is not an easy matter 



382 THE ORAL TISSUES 

to explain the presence of the vesicles over the teeth of succession 
because of the presence of the absorbent organ, and nearly always 
follicular odontomes are formed in connection with the members 
of the permanent series. The authors just cited believe that this 
fact — viz. the occurrence of vesicles — furnishes an explanation of 
the manner in which cystic tumours containing unerupted teeth 
arise. "Fluid collects between the enamel and the tooth capsule," 
they say. Assuming this statement to be correct, and although 
no mention is made of the enamel cuticle, one is led to ask "Whence 
comes the fluid? Why does it collect?" And one is told that 
fluid is normally and universally present over the crowns of un- 
erupted teeth. If this were so, one would expect to find that 
follicular odontomes were extremely common, which they are not, 
and that unerupted teeth could never remain in an innocuous state 
in the bones of the jaws, which they do. 

Paul, writing in 1894, observed: "On dissecting them (i.e., the 
teeth of sheep and monkey in their sacs), it appears that at a certain 
stage the crown of the tooth was quite free inside the sac, but that at 
a slightly later stage the sac adhered to the tooth, although it could 
be easily stripped from it." 

The above named authors proceed: "As the cyst enlarges, the 
contiguous bone is removed to make room for it, fresh bone being 
concurrently deposited on the outside of the jaw. In the case of such 
cyst lying in front of a tooth which is being cut, it is obliterated by 
the advancing tooth or it bursts; but when situated deeply in the 
jaw, a cystic tumour may be the result." 

Finally, Heath defines follicular odontomes as "cysts [which] 
contain one or more teeth in their interior or in their wall. The 
teeth may be well formed or may be quite rudimentary, consisting 
of irregular masses of bone and enamel." 

The Origin of the Cystic Fluid 

Already the opinion has been expressed that the fluid contents 
of these tooth-bearing cysts is derived from the degenerated cells 
of the stellate reticulum of the enamel organ. Instead of becoming 
absorbed in the usual way, they may, for some recondite reason, 
not disappear, but may further degenerate and liquefy, and produce 
a potential cavity which, on being filled with fluid, is the beginning 
of the formation of the cyst. 



ODONTOMES AND ODONTOCELES 383 

General Observations 

As bearing on the pathology of these cases, it is necessary to recall 
as succinctly as possible the anatomical topography of the parts, 
and to explain the grounds for the belief that the liquefaction of the 
stellate reticulum would account for the fluid in a dentigerous cyst. 
The enamel organ at maturity consists of four different cell elements, 
arranged from within outwards, as the (1) internal epithelium or the 
ameloblasts — elongated, columnar cells, measuring 15^ to 20ju, set 
in immediate apposition; (2) the stratum intermedium, a narrow 
layer of small polygonal cells; (3) the stellate reticulum, mucoid cells 
with round nuclei and numerous long branching processes; and (4) 
the external epithelium, a layer of single rounded or flattened cells. 
The functions of these are supposed to be as follow: The first to 
form enamel, and, when "spent," the translucent pellicle, or inner 
layer of Nasmyth's membrane; the second to recruit or rehabilitate 
the ameloblasts; the third to act as a "packing" material to the 
enamel organ; and the last (somewhat doubtful, but believed by 
some — Professor Paul, for instance) eventually to constitute, on 
persistence, the cellular layer of the enamel cuticle. Now, outside 
this external epithelium, which, it is important to note, is in direct 
continuity with the fibrous tissues which form the dental capsule — 
there is no sharp line of demarcation between the two, though in 
speaking of the two structures one unconsciously dissociates them — 
comes the capsule or tooth-sac itself. Composed, when young, of 
fibrous tissue with a feeble supply of round cells, it contains numerous 
gland-like epithelial bodies. 

It is therefore clear that the dental capsule usually has, on its 
internal aspect, a layer of epithelium — viz., the external epithelium 
of the enamel organ. It is possible, in fortunate circumstances, to 
show the lining of the capsule. To give a concrete example: If 
an unerupted first premolar be removed at the age of 7 to 7^, and 
its soft-tissued investment allowed to remain in statu quo ante, on 
making vertical sections one can see, under the 4 mm. objective, the 
ameloblasts becoming converted into the translucent pellicle of Nas- 
myth's membrane. At the cervical margin of such a tooth they are 
elongated and cylindrical, but little altered from those of activity — ■ 
merely shorter. Higher up, nearer the cusps of the crown, however, 
they are shrunken and flattened, and while still retaining their 
prominent nuclei, often become hexagonal or pentagonal in outline. 
In the neighbourhood of the extremities of the cusps they have 



384 THE ORAL TISSUES 

become fused to form a homogeneous membrane — the pellicular or 
inner layer of Nasmyth's membrane. Next to them is a single 
flat layer of cells, the external epithelium closely applied to their 
surface. Though so intimately approximated there is a wide range 
of difference from an embryological point of view between the two, 
the external epithelial cells being ectodermic and the dental capsule 
mesodermic in origin. 

Now, if the stellate cells of the enamel organ undergo further 
softening, disintegration and liquefaction, the first stage of the forma- 
tion of a follicular odontome is inaugurated. Little by little the 
fluid collects, until a cyst is produced, with the external epithelial 
cells on the outside and the internal epithelial cells on the inside. 
The first form a definite layer of epithelial cells and are not 
secretory cells. The second has sometimes not had an opportunity 
of becoming metamorphosed into the pellicle of the enamel cuticle 
(this is quite conceivable, and, really, a common-sense view) on 
account of the accumulation of the fluid; hence its absence on three 
authenticated occasions. At other times the fluid has probably 
collected after the production of the pellicle had occurred, but the 
cellular layer, instead of appearing on the surface as part of Nas- 
myth's membrane, remained as the adventitious lining of the cyst 
wall. 

Another fact in agreement with the opinion which is being pos- 
tulated is the striking anatomical resemblance between the degenerate 
cells of the stellate reticulum and the degenerating cells of an epi- 
thelial odontome. 1 

The majority of the epithelial bodies, derived from the fenestration 
of the tooth band, may give rise to the eruption cysts or epithelial 
odontomes, supernumerary teeth, etc. 

It is also conceivable that for some reason or other the cells of one 
or more of these gland-like bodies might undergo karyokinesis, and, 
like the paradental "rests," though in consequence of a dissimilar 
stimulation, might rapidly multiply, form large epithelial masses, 
of which the central cells, cut off from their nourishment, would die, 
degenerate, and liquefy. Here, then, a cyst might form — a capsular 
cyst — but if it were evolved from the central portions of the dental 

1 The phenomena associated with this degeneration were thoroughly described 
by Eve in an important paper on " Cystic and Encysted solid Tumours of the 
Jaws, with Observations on the Structure of the Enamel Organ," which he read 
before the Odontological Society of Great Britain in 1885. From his remarks it 
was apparent that he had corroborated the results of the researches of Falkson 
and Bryck of Germany, who had independently arrived at similar conclusions. 



ODONTOMES AND ODONTOCELES 385 

follicle, there would ultimately be found two layers of heteromorphic 
cells in the perfected follicular odontome wall; and this is never so. 
A follicular odontome is therefore an example of a congenital 
anomaly. 

HISTOLOGY 

Sections through the entire wall of a follicular odontome reveal 
most externally, an exceedingly thin layer of the mucous membrane 
of the gum, the epithelium of which is not more than a dozen cells 
deep. The outermost are flat, with compressed nuclei; the inner 
are cubical, as usual. 

Below the oral epithelium the fibrous tissue of the substance of 
the gum and the periosteum of the bone are found. 

The bony wall enclosing the tumour, and expanded by its devel- 
opment, has necessarily become very attenuated. The measure- 
ments of the diameters of the bone and gum tissue vary from 0.1 
mm. and 0.3 mm. respectively. 

The cyst wall proper, which may have a dimension of 0.5 mm. in 
width, lines the inner surface of the bone, and consists of dense 
strands of longitudinally arranged connective-tissue fibres, which 
are thick and strong, but loose in texture nearest the bone; while 
gathered into bundles further in, composing the bulk of the cyst, 
are connective-tissue fibres and cells, all freely supplied with blood- 
vessels. The former interlace in every direction, and sometimes 
are so thickly placed together as to present the appearance of 
longitudinally cut muscle fibres. The latter, of large size, run 
in opposite directions to those of the fibres. 

A thin layer of epithelial cells exists on the most internal aspect 
of the cyst wall forming its direct lining. 

The central cells cut off from all nutritive sources soon atrophy, 
die, and become disintegrated, and a cleft is formed. Cystic fluid 
is then produced. 

Ultimately a fully developed follicular odontome is lined with 
a layer of epithel al cells, one or more deep. The contents stain 
indifferently, consisting microscopically of an amorphous material. 
From pressure of the accumulating materials the cells become flat- 
tened, except those on the extreme edge of the cyst. 

Fibrous odontomata (endosteal fibromata) are merely hyper- 
trophies of the outer portion of follicular odontomes; and Cementom- 
ata are either an (i) ossification of fibrous odontomata, or(ii) over- 
growth on the part of the osteoblasts in the root membrane. Such 
probably was the origin of the cemental nodule described on page 80. 



386 THE ORAL TISSUES 

Compound Follicular Odontomes 

These are extremely rare in man; but cases have been recorded 
in the horse and goat. Sir John Bland-Sutton considers that they 
arise from the dental capsule, the osseous masses which are a char- 
acteristic feature being the result of sporadic ossification of the 
fibrous tissue composing this structure. He found five hundred 
denticles in the right antrum of a girl aged 11, and Ward Cousins 
(Brit. Med. Journ., June, 1908) one hundred and nine in the region 
of the second right mandibular molar in a boy aged n. . The latter 
partook of the nature of masses of hyperplasic cementum. 

An interesting case has been recorded by Bland-Sutton. An 
antral tumour of two years' growth, in a patient aged n years, was 
found to contain soft vascular tissue, inclosing a vast quantity of 
bony particles. More than five hundred such pieces were counted. 
Microscopical examination of the particles showed their structure 
to approximate that of cancellous bone identical with the alveolus 
of the jaws. 

Radicular Odontomes 

Origin. — An aberration of the dentine germ, being therefore con- 
fined principally to the root portions of teeth. 





Fig. 339. Fig. 340. 

Fig. 339. — Radicular odontome; lingual aspect. Actual size. 
Fig. 340. — Radicular odontome; mesial aspect. Actual size. 

Macroscopical Appearances. — As types of these and composite 
odontomes, the two following cases recently described by Dolamore, 1 
may be cited. 

Occurring in a patient of 14 years of age, a large " flattened enamel- 
covered tooth-like structure" was found in the region of the right 
mandibular lateral incisor. It had a second conical mass fused to 
its lingual surface, which ended below in a smooth bulbous tumour 
(see Figs. 339 and 340). Its weight was 2.7 grammes. Its measure- 
ments were 1.2 cm. in the anteroposterior, 1.9 cm. in the vertical, 
and 1.6 cm. in the lateral diameter. 

'Journ. Brit. Dent. Assoc, 1902. 



ODONTOMES AND ODONTOCELES 



387 



HISTOLOGY 

It is difficult to convey by means of mere words or illustrations 
a precise account of the structure of the conglomerate mass of a 
tooth tumour; the reasons being, that the hard tissues are so inex- 
tricably confused and present so many varied histological appear- 
ances which are almost indescribable. At the best of times, there- 
fore, the patho-histology can be but feebly interpreted. 




Fig. 341. — Two radicular odontomes. 

Sagittal sections having been made, it was found that the incisor, 
in the case under consideration, is remarkable for the dense pigmenta- 
tion of its enamel; the brown strias of Retzius are immature, while 
the lines of Schreger are altogether wanting. The tooth itself is 
long. Immediately behind it, i.e., on its lingual aspect, appears 




Fig. 342. — Radicular odontome of an incisor or maxillary canine. 

another smaller cone-shaped tooth with thick enamel, and a nar- 
rowed occluded pulp chamber. More internal still is a third 
dome-shaped denticle, the enamel of which is fused with that of the 
preceding (Fig. 343). The dentinal system is absent, the centre of the 
denticle being composed of a large amount of amorphous or irregular 
osseous material. Following this, and forming the remainder of the 
upper and inner surface of the odontome, are several masses of 



3 88 



THE ORAL TISSUES 



enamel intimately fused, the innermost one of all resembling a nar- 
row cone with an arrangement of dentinal tubes. The extreme 




FlG. 343. — Sagittal section of a radicular odontome. Prepared by grind 
ing. Unstained. Magnified 50 times. E. Enamel; D. Dentine; o. Osseous 
tissue. 



fine point of enamel has blended with the intervening mass. Passing 
still along the periphery of the neoplasm, and situated at its inner- 



ODONTOMES AND ODONTOCELES 



389 



most portion, are several radiatory dentinal systems, but no cemen- 
tum. At its base a slight amount of hyperplasic, lacunated cemen- 
tum is found. As it passes up to the labial surface once more, the 
cementum is a structureless, narrow band, approximating accurately 
to the normal type. 

The greater bulk of the tumour consists of fine-tubed dentine, 
and amorphous osseous substance with occasional large cavernous 
spaces. Deep down at the base of the second denticle are apparently 
the remains of three more irregular, dwarfed, rudimentary outlines 
of incisor teeth, each having enormously thick coatings of deeply 




Fig. 344. — Radicular odontome. Magnified 45 times. 

collection of G. W. Watson.) 



(From a section in the 



pigmented enamel of a low type, and fine-tubed dentine. Marked 
lines of demarcation exist between these dentinal systems and the 
bony deposits. No signs of absorption can be detected; but in 
places a few layers of interglobular spaces, and also enormous fusi- 
form cavities, filled with debris, occupy the intervening zone. 

The odontome is instructive because, being a root tumour, there 
is less than the ordinary amount of cementum. If one may venture 
to hazard an opinion as to its genesis and further development, it 



39° 



THE ORAL TISSUES 




Fig. 345. — Another radicular odontome. Magnified 45 times. (From a section 
in the collection of G. W. Watson.) 




Fig. 346. — Another portion of the preceding. Same magnification. 



ODONTOMES AND ODONTOCELES 39 1 

would seem to have been produced by a fusion of several more or 
less complete, ill-shaped enamel organs, each of which had attained 
an unusual degree of physiological activity, which was, however, 
profoundly modified by certain pathological conditions of growth. 

The accompanying illustrations show the histology of two ra- 
dicular odontomes in the possession of G. W. Watson, of Edinburgh. 
Fig. 344 exhibits the dentine of the root with a new growth, made 
up of ill-formed (?) osseous material, of which the following are the 
chief features: — (i) Large vascular channels; and (ii) matrix con- 
taining irregular spaces and branching processes, not, however, 
sufficiently well organised to be designated lacunae. In the greater 
part it is coarsely granular, the matrix being arranged often in more 
or less spherical bodies of varying sizes. At the periphery there are 
many large thickened masses of hyperplasic cementum, the enamel 
and dentinal teeth systems being suppressed. 

In Fig. 345 it is seen that the neoplasm bears some resemblance to 
plici-dentine. Many dentinal systems are present, with very 
granular dentine matrix and radiating tubes. Cementum and 
enamel are absent. 

Composite Odontomes 

Origin. — Aberrations and abnormalities in the development of 
the whole or part of the constituents of the tooth germ. Apparently 
they are confined to man, but they are very rare. 

Macroscopical Appearances. — An odontome of this type, recorded 
by Dolamore, appeared in the right molar region of the mandible 
of a male aged 22 years. Its measurements after removal were 
4.2 cm. in length, 2.8 cm. in depth, and 1.6 cm. in width, and 
total weight 24.5 grammes. This makes it one of the largest ever 
described. 

''Clinical History. — The patient stated that he first had pain 
about three years previous to his visit to the Hospital. He came 
under the impression that there was a root of a tooth troubling him. 
There had been swellings which came and went. The suppurative 
inflammation which occurs almost universally around these odon- 
tomes when they 'erupt, ' appears to be due to the density of their 
structure. The soft structures forming the lining membranes of 
their sockets, even though it is also the forming organ, can have 
but slight 'hold' upon them and readily become detached. Hence 
they become more comparable to sequestra than to pulpless teeth, 



392 



THE ORAL TISSUES 



in which there remains, through the cementum, a gradual transition 
from the living cells of the pericementum to the dead dentine. 

"Appearance in situ. — The molar and second premolar teeth are 
absent on the right side, the first premolar root remaining. A 





Fig 347. — A composite 
odontome from region of a third 
right mandibular molar. 



Fig. 348. — Another aspect of same 
odontome as in preceding figure. 



roughened, hard surface occupied about the situation of the second 
molar tooth, being distinctly posterior to the normal position of the 
first molar. A pointed probe could be passed vertically downwards, 
at the anterior surface of the tumour, to a great depth. At the 




Fig. 349. — Composite odontome, with portions of the capsule adherent to 

it, and the third molar placed in situ. The tumour is viewed on its lingual 

aspect. From an original photograph. Actual size. e. Portion which was 
erupting; w. Crown of third molar. 

posterior margin of the exposed surface the probe passed in a slant- 
ing direction downwards and backwards. The margins of the gum 
were slightly inflamed, and there was a slight amount of pus. The 
two surfaces of the mandible were markedly protuberant, the en- 



ODONTOMES AND ODONTOCELES 



393 



largement extending from the anterior margin of the tumour towards 
the angle. 




Fig. 350. — -A composite odontome. Prepared by grinding. Unstained. 
Magnified 50 times, e. Enamel; d. Dentine; o. Osseous material. 

"Removal. — A curved root elevator, passed down the anterior 
margin, slowly levered the mass out of its bed, gouging out with it, 



394 THE ORAL TISSUES 

and adherent to it, a portion of a fibrous-like capsule. On examina- 
tion, this capsule and the overlying odontome showed on the lower 
and outer posterior portion the imprint of a molar tooth. This 
was found implanted in the wall of the 'socket' of the odontome, 
whence it was readily removed with an upper root forceps. The 
remainder of the capsule gave to the 'socket' the 'velvety-like lining' 
mentioned by Jordan Lloyd, in a case he has described. 

The size and weight of the odontome, and the comparative ease 
with which the tumour could be removed with the elevator were 
outstanding features of the case." 

HISTOLOGY 

The periphery of this composite odontome is made up of fine-tubed 
dentine, the constituents of which are arranged in a curiously cen- 
tripetal fashion. Thus, instead of running from within out, as 
in an ordinary manner, these pass from without inwards, some- 
times for a considerable distance. The centre of the growth con- 
tains many small, irregular islands of enamel. Traces of absorption 
can be seen, where dark bands of enamel have been deposited in the 
spaces in the dentine, matrix. Interglobular spaces very frequently 
abound. 

The "osseous" material (Fig. 354) which composes the great part 
of the growth is probably merely dentine matrix full of irregular, 
interglobular spaces and canals. No cementum as such exists; 
repeated examinations of the section made transversely to the body 
of the odontome have failed to show lacunae and canaliculi. In 
one place, the appearances represented by a crude form of plici- 
dentine may be noted. 

An interesting and valuable feature of this tumour in the presence 
of its fibrous capsule (Fig. 355). Sections of this reveal several 
structures. First, the soft investing tissues are made up of small 
round cells with one, and sometimes two, large round nuclei in their 
interiors, also long fusiform branching cells containing elongated 
flattened nuclei, all embedded in a delicate white connective tissue 
stroma. Blood-vessels abound, and are more numerously distri- 
buted at the surface, directed towards the body of the tumour. 

Sections have been cut in which the relationship of the bone and 
capsule have not been disturbed. The result shows the probable 
method of formation of the dentinal substance (Fig. 356). At the 
attached maigin of the capsule, multitudes of osteoblasts cohere to 



OUONTOMES AND ODONTOCELES 



395 




Fig. 351. — Composite odontome. The section is a portion of the periphery 
of the growth, the dentinal tubes running outwards to the left, the remainder 
consisting of amorphous dentine matrix with absorption areas intervening. 
Prepared as in Fig. 343. Unstained. Magnified 45 times. D. Dentine; o. 
Osseous material. 




Fig. 352. — Same as the preceding figure, but from another portion of the 
periphery. Prepared as in Fig. 343. Unstained. Magnified 45 times. 



396 THE ORAL TISSUES 

the margin of the dentogenetic zone, or what corresponds to this 
zone of formed but uncalcified tissue in developing dentine. This is 
a clear, translucent band, in which are found not only the familiar 
calcospherite spherules, but also rudimentary empty tubes (Fig. 
357). The osteoblasts are closely placed side by side, and are seen, 
here and there, to be embedded in cloudlike masses of amorphous 
stained albuminous material. Osteoclasts sometimes mingle with 
osteoblasts. 




Fig. 353. — Composite odontome. Shows enamel and amorphous dentine 
fused together, the dark masses being the highly pigmented enamel, the lighter 
portions the dentine. Magnified 45 times. E. Enamel; d. Dentine. 



Here there are apparently direct and irrefutable evidences and 
proofs that round cells, osteoblastic in shape and nature, are the 
factors concerned in the building up of dentine, the empty tubes 
being probably the remains of the connective-tissue stroma of the 
capsule. Thus, again, are corroborated, in an instructive and un- 
looked-for manner, the hypotheses which would relegate to the 
odontoblasts of the pulp a more important function than dentine 
building, and assign this physiological process to the round osteo- 
blastic cells seen on the surface of the pulp, as well as on the free 
edge of the fibrous capsule of this composite odontome. 



ODONTOMES AND ODONTOCELES 



397 




Fig. 354. — To show the amorphous, irregular character of the dentine comprising 
the greater part of the body of the odontome. Magnified 45 times. 




Fig. 355. — Capsule in situ. 
th3 lower the fibrous tissue. 
A, Albuminoid material. 



The upper part of the photograph is dentine, 
Magnified 45 times, d. Dentine; c. Capsule; 



398 



THE ORAL TISSUES 




Fig. 356. — Same as the preceding, showing 
Dentogenetic zone intervening. 



, d. Dentine, c. Capsule, 
Magnified 240 times. 



and dz. 




Fig. 357. — The same as the preceding, to show the calcospherite spherules and 
empty tubes in the dentogenetic zone; below which are dark masses (a) of deeply 
stained albuminous material. Magnified 600 times. 



ODONTOMES AND ODONTOCELES 399 

ODONTOCELES 

Similar clinically to odontomes, but differing very considerably 
in a pathological and pathogenetic sense are the odontoceles or tooth- 
cysts. An odontocele differs from an odontome, which is a tooth- 
tumour, in the facts that it is dissimilar in origin, and that the tooth 
associated with it shows certain structural deviations from the 
normal, in which loss or addition of tissue, either from maldevelop- 
ment or as a result of inflammatory action, is a conspicuous feature. 

Varieties. — (i) Sub-capsular, (ii) Extra-capsular. 

INTRODUCTORY 

The types which are about to be narrated, possessing a few com- 
mon characteristics or relationships, are very dissimilar from a 
pathogenetic point of view, and, at the same time, are extremely 
remarkable and interesting. They serve to illustrate the belief 
that greater precision is required of dental surgeons when describing 
certain pathological changes that may take place in the osseous 
framework of the maxillae and mandible. 

There is room for an amplification and revision of the nomencla- 
ture employed in the subject of dental pathology, and new terms 
must necessarily be introduced to more accurately represent con- 
ditions as knowledge of the special pathology of the teeth ad- 
vances. It is necessary to throw some light on the obscurity of 
the origin of cysts of the jaws, and to ascertain in what circum- 
stances or through what agencies fluid is produced in such amount as 
to constitute the chief clinical characteristic. Their signs and 
symptoms are unimportant and uninstructive, but the morbid condi- 
tions and the patho-histology of the tissues are of extraordinary 
significance. If the deductions arrived at are inconclusive, or 
open to another construction, allowance must be made for the 
difficulties attaching to the research and to the great mystery sur- 
rounding the unique display of morbid phenomena. 

It will be found that odontoceles can be divided into two classes. 
Thus one would be designated an example of a Sub-capsular odon- 
tocele, and the other of an Extra-capsular odontocele. They merely 
fall into the same main category because, in the opinion of the au- 
thor, they cannot strictly be placed under any other classification. 

A common feature here is the existence of a unilocular cyst in the 
jaws, containing an anomalous tooth — non-erupted, and so-called 



400 THE ORAL TISSUES 

"encysted," disclosing itself in adult life. It is incorrect to describe 
"a case of an encysted tooth;" the fact that it is imbedded in the 
bone does not of necessity mean a disease of the tooth or jaw, but 
a state of being or condition in which the tooth happens to exist. 
One is led to understand, from the pages of text-books and cur- 
rent literature, that a buried, "imprisoned" tooth, as it is somewhat 
fancifully called by Roswell Park in The Principles and Practice 
of Modem Surgery, 1908, may induce a passive or active reaction to 
the containing tissues. Thus (1) it may, usually, remain in its 
uncommon irregular position undisturbed, unnoticed, inert, impacted 
or otherwise throughout the life cycle of the individual, giving rise 
to no signs or symptoms of anomaly; or (2), it may, rarely, originate 
a tumour, through the production and accumulation of a fluid 
body around it. Clinically, when a tense, fluctuating, non-inflam- 
matory, painless swelling of the jaw presents itself for diagnosis, 
either a dental cyst or a follicular odontome is first brought to mind. 
These two, and especially the former, are the commonest cysts 
with which the dental surgeon has to deal. But other species of 
cysts may occur at times, and it is possible to fully enumerate them 
in their probable order of frequency. 

SPECIES OF CYSTS OF THE JAWS, BASED ON THEIR PATHOLOGICAL 

VARIATIONS 

(1) Dental cysts. 

(2) Eruption cysts. 

(3) Follicular odontomes — simple or compound. 

(4) Epithelial odontomes or multilocular cystic tumours. 

(5) Mucous cysts of the antrum. 

(6) Odontoceles: (a) Sub-capsular, (b) Extia-capsular. 

(7) Cystic adenomata of the antrum and gum. 

Of the varieties of odontoceles, the sub-capsular form occurs in 
the young — from 10 to 20, the extra-capsular form later in life. 
Two illustrative cases follow. 

A 

A Sub-capsular Odontocele. {The case of Mr. R. L.) 

On examination of the mouth a large, smooth, bluish, fluctuating, 
painless distension of the bone was seen occupying the right canine 
region of the mandible. Its presence had been detected subjec- 



ODONTOMES AND ODONTOCELES 



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402 THE ORAL TISSUES 

tively only five weeks previously. The canine was missing, and 
there was no history of its having been extracted, though several 
teeth had been removed and a denture was being worn. The first 
premolar was almost in contact with the distal surface of the second 
incisor. The corresponding tooth was not in evidence, but both 
left canines were erupted in correct alignment with the dental 
arches. A cyst was diagnosed. Radiographs disclosed the following 
condition of the parts: At the base of an extensive cavity in the 
bone, measuring 2.5 cm. by 2 cm. by 1.5 cm., was a canine, non- 
erupted, non-impacted, non-absorbed. It was placed vertically 
in the jaw, its crown pointing upwards and extending into a some- 
what triangular hollow, produced by the divergency of the roots of 
the second incisor and first premolar. Examination of these roots 
showed no visible areas of absorption whatever, though the latter 
appeared to be twisted. On inspecting the radiograph of the canine 
it was at once apparent that there was a loss of substance — i.e., 
enamel and dentine — at the summit of the cusp. It was possible 
to trace a direct line of continuity between the cystic contents out- 
side the tooth and the pulp itself. 

On excising the cyst wall there was no venous haemorrhage, as 
had been anticipated from the colour of the tumour. Instead, the 
cystic contents were deeply discoloured and almost black. It was 
this that had imparted the blue appearance by reflected light to 
the oral tissues, a phenomenon similar to that frequently witnessed 
in connection with hydroceles of the tunica vaginalis. The tooth 
was removed and the cyst wall dissected out; granulation tissue soon 
formed, and at the end of ten months healing had taken place, a 
mere shallow depression on the surface of the jaw marking the site 
of the odontocele. 

The tooth was at once carefully tested for the presence or absence 
of Nasmyth's membrane. The inner layer was found, but no 
cellular layer. It was then treated by the Koch-Weil method, and 
the section showed that the tip of the crown was defective and its 
growth had never been completed. There was no absorption of 
tissue. A hollow, tube-shaped core occupied the vertical axis of 
the upper part of the tooth. Had it erupted in the ordinary manner 
it is impossible to guess what the consequences would have been. 
Soft tissue, composed of small cells, extended vertically into the 
pulp cavity, and also slightly laterally, in places, into the dentine. 
The pulp itself was composed, at its coronal portion, of broken-down 
cells, the odontoblasts were unrecognizable, the nerve bundles 



ODONTOMES AND ODONTOCELES 



403 



obliterated, while a few long endothelial-like cells closely applied 
in bundles represented the collapsed and shrunken walls of the 
vascular system. It is impossible for anyone to say what had hap- 
pened to the enamel organ at that part which was going to form the 
summit of the crown. It could not have been due to septic disease 
of a deciduous predecessor, for one would then probably get the 
whole of the enamel organ deranged with regard to its usual func- 
tions. Apparently there was a sudden cessation of the work of the 
ameloblasts at that spot, leaving not only a breach of surface but a 
direct opening into the pulp cavity. After suitable preparation the 




p p 



Fi<;. 358. — Longitudinal section of canine described in text. E. Enamel; 
p. Pulp cavity; pp. Pulp tissue extending laterally into dentine; I. Incisive edge- 
of tooth. Magnified 20 times. 



cyst wall was microscopically examined. It was very thin, only 
measuring 0.25 to 0.75 mm. Composed of firm fibrous tissue it had 
a lining of numerous soft, large epithelial cells, held loosely together 
by a frail cementing substance. It was in no sense a compound 
epithelium, as seen sometimes in both dental cysts and follicular 
odontomes, nor were they secretory cells. It was, probably, the 
external epithelium of the enamel organ swollen by absorption of 
cystic fluid, and the cyst wall was nothing more nor less than the 
dental capsule itself. 

To the accident of the presence of a congenital lesion of the hard 



404 THE ORAL TISSUES 

parts of the crown, and not to impaction or delayed eruption, 
can be attributed the evolution of this cyst. Here is, then, an 
example of a sub-capsular odontocele — i.e., a cyst originating 
beneath the capsule or follicle of an abnormal tooth, as a result of 
the effusion of lymph from the neighbouring blood-vessels, into a 
potential cavity produced by a developmental defect of the summit 
of its crown. It may be suggested that the same morbid phenomena 
might have been induced by serous exudation into a space or spaces 
of a vacuolated follicle. But here the capsule had undergone no 
such retrogressive metamorphosis on account of its being retained 
in the jaw, as already mentioned. Hence the opinion that a cavity 
had existed through something unknown happening to the formative 
cells of the enamel organ many years ago, and effusion of lymph 
into the cavity thus created. 

B 

An Extra-capsular Odontocele. 1 (The case of Dr. C. N.) 

Interesting and instructive as is the case just detailed, the second 
variety of odontocele is even more remarkable. 

Past history: The maxillary incisors and premolars had previously 
been removed. One was broken, two were quite sound, and caries 
was present in the rest; the sound teeth were sacrificed for the 
purposes of giving firmer hold to a bridge which was to be con- 
structed. The denture was worn for ten years. About three weeks 
before the tumour "became cystic" — to quote the patient's own 
words — he broke the plate through the middle, and he continued 
to wear it, being too busy to have it attended to. He believes that 
the movements of the fractured appliance irritated the jaw, and 
"stirred the latent tumour into activity.' His dentist pointed out 
to him ten years previously that the permanent maxillary canine 
in the right side was missing, and had apparently never erupted. 

Present history: "The patient's attention was first directed to a 
small enlargement of his cheek. He noticed it when washing his 
face, being conscious that the right cheek was fuller than the left. 
On feeling it more carefully he could make out a round, hard promi- 
nence close by, and at the same level as the right ala of the nose. 
His first impression was that an alveolar abscess was forming, but 

1 A similar case — the second to be recorded — was detailed by Mr. J. Alan 
Forty and the author in a paper presented to the International Dental Congress. 
1014. 



ODONTOMES AND ODONTOCELES 405 

it did not make any progress in the way of 'ripening.' About two 
weeks later a little swelling appeared in the mouth in the angle 
between the upper lip and the gum, and in the region of the second 
incisor and canine tooth. This was fluctuant, and the patient 
thought that it probably contained pus. He incised it, but did 
not evacuate any pus, and in a few days it had attained the same 
size again. He then called in a brother practitioner, who incised 
it down to the bone, and it was then apparent that the swelling was a 
cyst. It soon filled up and became considerably larger, and the 
patient then thought it advisable to consult a surgeon with the view 
to its removal. Up to this point there was no pain associated with 
it beyond a throbbing in the gum and part of the hard palate." 





Pig. 359. Fig. 360. 

Fig. 359. — A right maxillary first incisor contained in an extra-capsular odonto- 
cele in a boy of 10 years. Labial aspect. Shows a calcareous nodule attached to 
the enamel. {Mr. Alan J. Forty's case.) 

Fig. 360. — Another aspect of tooth of preceding figure. Shows a calcareous 
nodule attached to the enamel. 

' The patient saw a leading operating surgeon who examined the 
cyst and advised its removal. A few days later he proceeded to do 
this, and on dissecting off about a third of the cyst wall he found it 
firmly rooted to the bone of the maxilla. He sheared off the 
dissected portion of the cyst close to the bone with the view to its 
pathological examination and further operative treatment. From 
the clinical appearance he was of the opinion that the tissue was 
malignant in character. Examination was made of the detached 
portion, and on the patient's return two days later, he was informed 
that the tumour was of the nature of a myeloid sarcoma. This 
diagnosis, however, was disputed by the pathologist who, as a 
personal friend of the patient, was called in to give an opinion. He 
was very emphatic that there were no tissue elements to warrant a 
diagnosis of malignant disease, and it is only fair to the operating 
surgeon to say that he abandoned the diagnosis of myeloid sarcoma, 
and consented to perform a much more modified operation than he 
originally intended, although still feeling that there was a malignant 



406 



THE ORAL TISSUES 



element in the case. The operation decided upon was to remove the 
affected area with a margin of healthy tissue around it. This was 
done, a wedge-shaped portion of the upper jaw being removed, and 
a considerable part of the bone of the anterior wall of the antrum 
included, the membrane being left. The cavity in the mouth healed 
up without any difficulty, although the antrum became affected and 
necessitated douching through the nose. Eventually the wound 
closed completely, and the mouth has remained sound and well 
after a period of twelve months." (Patient's report.) 

Appearance of the tumour: The specimen consisted of a V-shaped 
piece of tissue bounded internally by the median line of the palate, 
and externally by a line running backwards and inwards through 





CM 



P 
Fig. 361. Pig. 362. 

Fig. 361. — Extra-capsular odontocele, as viewed from mesial aspect; p. 
Palatal surface; L. Labial surface, where fluid accumulated; c. Canine; cm. 
Calcined mass. 

Fig. 362. — Tooth everted from its surroundings to show calcified nodule (n) 
attached to surface of crown. 



the premolar region. Its width in front was 3.5 cm. The labial 
aspect showed an opening in the alveolar process 22.5 mm. long, 
9 mm. wide, the lower margin being placed 6 to 9 mm. from the 
free edge of the alveolar process. It was made by the incision for 
the evacuation of the cystic fluid. At its base, and at a distance of 
about 4 mm. from the surface, lay a calcified mass. The main 
object in the preparation was a canine fully formed and well devel- 
oped, 25 mm. in length. Its crown was almost entirely embedded 
in a solid mass of brittle, calcified material, which was yellowish 
in colour and partly translucent by reflected light. During the 
digital disturbances consequent on the operation this calcified cap 
had obviously been dislodged from the position it had occupied for 
many years and had become detached, and the crown of the tooth 
was shelled out from it with the exception of a small excrescence, 



ODONTOMES AND ODONTOCELES 



407 



which, still adhering to its distal aspect, gave the clue to the patho- 
logical conditions which had been occurring. The nodule measured 
4 mm. in length, the dimensions of the hard cap being 14 mm. by 
12 mm. There were no marks of absorption on the surface of the 
enamel. Nasmyth's membrane was present. The calcified mass 
was obviously the dental capsule, which had undergone a retro- 
gressive metamorphosis. It had not been completely infiltrated, 
as portions still retained their fibrous characters (Fig. 361). Patho- 
logical calcification or petrifaction occurs almost without exception 
only in degenerating, dying, or dead tissue as Hektoen and Riesman 




FlG. 363. — Photomicrograph of crown of tooth described in text. 
c. Calcified nodule. Magnified 45 times. 



e. Enamel; 



record {op. cit.). Thus its appearance can probably be explained 
by the fact that the dental capsule of the unerupted canine had died, 
and formed a nidus for the lime-salt infiltration, thus differing very 
greatly from the follicle in the preceding Sub-capsular odontocele. 
The composition of the hard mass was found to be calcium car- 
bonate largely. On placing a fragment under the microscope, 
and allowing a weak solution of hydrochloric acid to run, by capillary 
attraction, beneath the cover glass, bubbles of gas were immediately 
evolved, the residue of organic material presenting an amorphous 
structure with a tendency to the formation of a pattern of spherules. 
Around the surface of this calcified capsule was developed the cyst, 



408 THE ORAL TISSUES 

and what was apparently the "bone of the jaw" mentioned in the 
patient's notes was its exposed surface. Histologically examined, 
the soft parts consisted chiefly of connective-tissue fibres with 
nmuerous small cells, changed connective-tissue corpuscles, tiny 
haemorrhages, clusters of fat cells, blood-vessels, and a small amount 
of bone which represented all the remains of the thinned and ex- 
panded external alveolar plate. The cyst wall was lined with epi- 
thelium. There were no microscopic signs of inflammation. 

Whence came the cystic fluid? It is difficult to determine. 
Eliminating every possible structural element in the gum which 
could give rise to a cyst, it might be conjectured that the cells of the 
walls of certain lymph spaces in the submucous tissues had broken 
down, and produced, by rapid multiplication, the cyst, through irri- 
tation from the friction of a loose, fractured mechanical appliance on 
the one side, and the hard unyielding surface of the ossified capsule 
on the other. 

At first sight the dental condition might have been regarded as a 
calcified follicular odontome. But this was not so. For the cystic 
fluid was outside, not inside, the capsule, which was not expanded, 
but remained, in spite of its petrifaction, closely adherent to the 
surface of the tooth. Hence it is an extra-capsular odontocele. 
Its origin may be explained by the breaking down of epithelium or 
endothelium in the soft tissues of the jaw lying between, and stimu- 
lated into growth by the pressure, and perhaps friction, of two hard, 
unyielding substances. 

There are some further problems surrounding this case which can 
never possibly be solved: The age of the patient when calcification of 
the capsule took place; the possibility or otherwise that this calci- 
fication, acting as an obstruction, was the cause of the non-eruption 
of the tooth; the histological characteristics of the actual structures 
in the soft superimposed parts, which, on breaking down, produced 
the odontocele; the date of its formation; and the nature of the still 
more mysterious forces which governed the impregnation with 
lime salts of the dead or dying follicle. 

The fact that mechanical agencies play a not inconsiderable part 
in the production of disease calls for no special comment. And teeth 
which undergo moliminous eruption, or do not erupt at all, as is so 
frequently the case with the third molars, may act as foreign bodies 
and produce inflammation and absorption of the surrounding parts, 
and even give rise to cystic tumours of the maxilla. ^ 



CHAPTER XVI 

ORAL MICROBIOLOGY 

Introduction — Classification of plants — Classification of Bacteria and 
Protozoa — Microscopic examination of oral material — Pathogenic 
organisms — The Pyogenic cocci — Filterable viruses — Adventitious 
bacteria of the' mouth — Micro-organisms of dental caries. 

INTRODUCTION 

In contributing a chapter on Oral Microbiology, one can but briefly 
outline the classification and characteristics of the organisms com- 
monly found in the oral cavity. It would be inexcusable to attempt 
the presentation of more than the dental phase of the subject, there- 
fore the reader is referred to standard works on the subject of Micro- 
biology, Bacteriology, and Protozoology for a detailed account of 
the micro-organisms. 

The oral cavity is a fertile field for the development of various 
types of micro-organisms. We find there a temperature suitable for 
the growth of a large percentage of the organisms, substances 
supplying nourishment, a sufficient supply of moisture and oxygen. 
Furthermore there are various crypts and spaces in which they may 
develop undisturbed. The organisms manifestly gain access by 
way of the mouth, being carried there with food, drink, instruments, 
etc., or, they may be carried in through the nasal passages with the 
inspired air. These organisms may be transmitted directly from 
other individuals. The investigator possessing this knowledge is 
not surprised at the variety found, but rather that more species 
are not encountered. 

Some micro-organisms do not find a suitable environment, and they 
will not multiply at all, or but to a very slight extent, in the oral 
cavity. Some are antagonistic to the development of others. 
Foods, drink and the saliva are constantly or intermittently not only 
diluting the organisms, but carrying many of them along the pas- 
sages into the gastro-intestinal tract, causing a diminution of the 
numbers and also changing, to some extent, the types found in a 
given individual from day to day. 

409 



4-IO THE ORAL FLORA 

Many of the organisms present are of no pathological importance, 
being of a type incapable of exerting a detrimental action on the 
tissues. Others, while possessing no pathogenesis in the strict sense 
of the word, are of great importance to the dental practitioner and 
pathologist owing to the fact that they play an important part, 
either directly or indirectly, in the condition known as dental caries. 
Various types of organisms are also encountered, which are capable 
of producing definite infections when local and general conditions 
such as will admit of their invading the tissues exist. 

On studying microscopically and culturally, the flora and fauna 
of the oral cavities of a large number of individuals, the investigator 
is always impressed with a number of facts of interest and also of 
great import. The most important of these are as follows: 

(i) The number of organisms in the oral cavities of different 
individuals varies markedly. 

(2) The more closely associated are individuals, the more nearly, 
other things being equal, does the micro-organismal content of their 
oral cavities correspond. 

(3) The number and types of micro-organisms vary in the oral 
cavities of all individuals to a great extent according to environ- 
mental conditions, food, etc. 

(4) The micro-organismal content is influenced directly by the 
degree of cleanliness the individual exercises as regards his oral 
cavity. 

(5) However cleanly one may be, it is impossible to remove or 
prevent the growth of all micro-organisms. 

(6) Certain types of organisms are encountered almost univer- 
sally in different individuals. 

(7) Micro-organisms possessing a definite pathogenicity may exist 
in the oral cavity of an individual without causing any untoward 
results. 

The greater number of the micro-organisms encountered in the 
oral cavity are Bacteria. Higher Fungi are found, a few varieties of 
Yeasts, and several varieties of organisms of various types, ordi- 
narily known as Moulds. Some of the latter are capable of producing 
pathogenic conditions, which, however, are not common. The 
protozoa have not been studied in the same detail as bacteria. 
There are, however, comparatively few varieties present. 

Before entering into a discussion of the various types of organisms 
found in the oral cavity and their significance, it is essential that the 



ORAL MICROBIOLOGY 411 

student be possessed with some knowledge of their morphology and 
physiology, also of their place in the biological world. 

Bacteria are microscopic, unicellular vegetable organisms, oc- 
curring either as small spheres, straight or curved rods, or as long 
threads, motile or non-motile, some forming endospores, multiplying 
by a process of transverse division or fission, devoid of chlorophyll, 
and nourished by a process of osmosis. 

These organisms are very minute and the individual cells can only 
be seen when magnified several hundred diameters; they average 
in size from about 0.4 to 1.5 y in diameter for the spherical forms, 
and from 0.8 to 4 y. long for the rod shaped, and 15 to 30 /x in length 
for the thread forms. 

Each individual organism consists of a single cell: in no instances 
are bacteria multicellular. The majority of the organisms classi- 
fied as bacteria are vegetable, and therefore belong to the plant 
kingdom. The morphological classification basically depends on the 
shape of the individual cells, as will be seen by consulting the 
list given, page 413. They are devoid of chlorophyll, the green 
colouring matter of many plants, which enables them to obtain 
nourishment, at least partially, from inorganic sources; consequently 
they are nourished by a process of osmosis. They divide by a pro- 
cess of transverse division or fission: therefore they are classed with 
the Schizophyta, or fission plants under the name of Schizomy- 
cetes or fission fungi, belonging to the group of plants known as 
Cryptogams. 

Certain of the bacteria possess long slender appendages, which 
can only be demonstrated by special methods of staining, called 
flagella. These are constantly in motion, and cause the organisms to 
move about in the substratum in which they are developing. The 
rapidity and mode of the movements give to the organisms a 
characteristic type of motility; many non-flagellated bacteria present 
an oscillatory motion known as Brownian or Brunonian motion. 

Certain bacteria produce small oval or spherical, highly refractile, 
glistening bodies, known as spores or endospores. When certain con- 
ditions are present, as deficient nutritive material, or moisture, or 
the presence of substances exerting a detrimental action on the or- 
ganism, small granules (the sporogenic granules) appear within the 
cellular protoplasm; these granules gradually coalesce in the centre or 
at one end of a cell forming the endospore. These endospores lie 
dormant until conditions are favorable for their development, when 
they germinate and pass into the vegetative stage. The vegetative 



412 THE ORAL FLORA 

cell is capable of multiplying by a process of transverse division. 
The statement is frequently encountered that some bacteria repro- 
duce by sporulation; this statement is, according to our present 
views, erroneous. 

In cultures of certain bacteria, cells are found which vary markedly 
from the normal types in size and shape. In some instances these cells 
have been called Arthrospores, the claim being made that they play 
a part in the reproduction of the organisms. These cells are in all 
probability involution forms of the organism, due to osmotic dis- 
turbances, and not true arthrospores. 

Yeasts are small oval or spherical vegetable organisms which repro- 
duce by a process of budding, at times producing small spherical or 
oval bodies known as ascospores. They are classed under the Eumy- 
cetes with the group of Ascomycetes. 

The Moulds include a group of organisms of various types whose 
common characteristics lie in the fact that they develop from spores 
forming a mycelium, which is the body of the fungus, to which are 
attached hyphae of various types, at the ends of which outgrowths 
appear which carry the spores or conidia, endospores or gonidia; or 
bodies are formed by the union of elements at the end of two hyphae, 
joining together, known as zygospores. 

There is a group of organisms allied to the yeasts and moulds 
which have resisted all attempts at proper classification, and are 
therefore grouped under the head of Fungi Imperfecti. Many mem- 
bers of this group are of great import from a pathological point of 
view. Some are encountered in the oral cavity. 

The following will give the student an insight into the relation- 
ships existing between the various plant groups. 

CLASSIFICATION OF PLANTS 

(A) S per mato gams, Spermatophytes, or Phanerogams, the seed 
plants. In this group are included the higher plants; all those 
reproducing by dissemination of seeds. 

(B) Cryptogams, including those plants reproducing by means of 
endospores or gonidia, exospores or conidia, budding and by trans- 
verse division of fission. 

Classification of Cryptogams with special reference to those organ- 
isms of importance from a pathological viewpoint. 
Division I. My xoth alio phyla, the slime fungi. 



ORAL MICROBIOLOGY 413 

Division II. Euthallophyta, the true thallophytes, namely those 
plants which cannot be differentiated into root, stem and leaf. 

(A) Schizophyta, fission plants: — 

a. Schizomycetes, fission fungi, cleft fungi, or bacteria, 

b. Schizophycece, cyanophycece or blue green algae. 

(B) Phycomycetes, fungi resembling algae: — 

a. Oomycetes, aquatic, not important, 

b. Zygomycetes, including many of the important moulds 
producing zygospores. 

(C) Eumycetes, true fungi: — 

a. Ascomycetes, important as certain pathogenic yeasts and 
allied organisms are included in this group, 

b. Basidiomycetes, 

c. Fungi imperjecti, important. This group includes a 
number of types, some pathogenic, the characteristics of 
which are of such a nature as to render it difficult to 
properly classify them. 

Division III. ThaUophyta, including green, brown, and red algae, 

not important. 
Division IV. Bryophyta, including liverworts and mosses, not 

important. 
Division V. Pteridophyta, including the ferns and other plants as 

lycopodium and adder's tongue, not important. 

CLASSIFICATION OF BACTERIA 

Order: Schizomycetes 

. Sub-order: Eubacteriacea (without coloured granules in cell con- 
tents; uncoloured except in a few species, which may produce a 
soluble or an insoluble pigment). 
I. Family: Coccacece (globular, becoming slightly elongated 
before cell division; cell division in one, two or three 
directions). 

(a) Genus: Streptococcus (cell division in one direction, 
united in chains, non-flagellated). 

(b) Genus: Micrococcus (cell division in one, two or three 
directions with separation of the cells, non-flagellated). 

(c) Genus: Sarcina (cell division in three directions, united 
in packets of eight, non-flagellated). 

(d) Genus: Planococcus (cell division in one, two or three 
directions, cells separate; flagellated). 



414 THE ORAL FLORA 

(e) Genus: Piano sarcina (cell division in one, two or three 
directions, cells united in packets of eight; flagellated). 
II. Family: Bacteriacece (cells straight, cylindrical, short or 
long rods without a sheath, non-branching; flagella present 
or absent; endospores present or absent). 

(a) Genus: Bacterium (cells straight, cylindrical, short or 
long rods, non-motile; flagella absent; endospores pres- 
ent or absent). 

(b) Genus: Bacillus (cells straight, cylindrical, short or long 
rods, motile, with peritrichous flagella varying in num- 
ber, endospores present or absent). 

(c) Genus: Pseudomonas (cells straight, cylindrical, short or 
long rods, occasionally in short filaments; motile; with 
flagella arranged at one end, monotrichous or lopho- 
trichous; endospores known in but a few species). 

III. Family: Spirillacece (cells more or less curved; rigid or 
flexile, cell division transverse to long axis of cell; flagella 
present or absent, monotrichous or lophotrichous). 

(a) Genus: Spirosoma (cells rigid, non-motile, without 
flagella). 

{b) Genus: Micros pira (cells rigid, motile, with one or two 
polar flagella). 

(c) Genus: Spirillum (cells rigid, motile, possess a tuft of 
polar flagella). 

{d) Genus: Spirochceta (cells flexile, sinuous, corkscrew-like, 
do not possess flagella but are motile, usually actively; 
motility due to undulations of membrane). (The 
majority, if not all, of the Spirochaeta divide by a 
different process than the bacteria and should be 
classed with the Protozoa under the Flagellata. Genus: 
Treponema). 

IV. Family: Mycobacteriaccm (cells straight, short or long, cylin- 
dric, clavate, cuneate in form, at times showing a true 
branching, or as long, branched mycelial filaments; no sheath; 
without endospores, but at times forming gonidia-like bod- 
ies due to transverse segmentation of cells). 

(a) Genus: Mycobacterium (cells commonly short, cylindrical 
rods, sometimes bent and irregularly swollen, clavate or 
cuneate; may present Y-shaped forms or longer fila- 
ments with true branchings; produce short coccoid ele- 
ments which may be gonidia). 



ORAL MICROBIOLOGY 415 

(b) Genus: Streptothrix (cells commonly long branched 

filaments; produce gonidia-like bodies; form aerial 

hyphae in cultures; causing resemblance to moulds). 

V. Family: Chlamydobackriacece (cells in the form of filaments, 

and surrounded by a distinct sheath; cell division 

transverse or in three directions, resulting in formation of 

gonidia-like bodies which may or may not be motile). 

(a) Genus: Leptothrix (filaments unbranched; division 
transverse). 

(b) Genus: Phragmidiothrix (filaments unbranched; divi- 
sions in three directions; sheath scarcely visible). 

(c) Genus: Crenothrix (filaments unbranched, division in 
three directions; sheath distinct). 

{d) Genus: Cladothrix (filaments show false branching). 
B. Sub-order: Thiobacteriacece (cells show presence of coloured gran- 
ules, or sometimes diffuse colouring red or violet). 
I. Family: Beggiatoaceoc (filamentous; with or without sheath; 
motile or non-motile sulphur granules in cell contents; go- 
nidia formation not known). 
II. Family: RhodobacteriacecE (cells irregular, globular, oval, 
cylindrical, non-filamentous; contents show the presence of 
sulphur granules or bacterio-purpurin, red or violet). 

PROTOZOA 

The Protozoa are microscopic, unicellular, animal organisms of 
various forms. Some occur in the oral cavity, but have not been 
studied in the same detail as the Bacteria. The most important are 
the following: 
Of the Flagellata: 

Genus: Treponemata, several species. 
Genus: Trichomonas, one or more species. 
Of the Sarcodina: 

Genus: Endamoeba; endamceba gingivalis of Gros. 
Other endamceba? 

MICROSCOPIC EXAMINATION OF ORAL MATERIAL 

Various representatives of the different groups, in the foregoing 
classification, will be observed when one mounts and examines 
microscopically preparations of scrapings from the oral mucous 



416 



THE ORAL FLORA 




Fig. 364. — The micro-organisms from a healthy mouth direct. Stained by 
Gram's method. Magnified 800 times. E.C. Squamous epithelial cell from 
surface of cheek; b. Rod-shaped form, probably Bacillus buccalis maximus; t. 
Thread form; D. Diplococci, probably Streptococcus brevis; s. Spiral form. 



E.C 



L R 




Fig. 365. — From same preparation. Balsam preparation. E.C. Epithelial 
cell; n. Nucleus of partially-digested epithelial cell; T. Thread forms; l.r. 
Leptothrix racemosa. 



ORAL MICROBIOLOGY 417 

membranes, especially in the buccal and alveolar sulci; from the 
surface of the teeth; collections of food debris on the teeth, or in 
protected surfaces; soft salivary calculus; exudates from alveolar 
abscesses, gingival infections and various pathological processes in 
different parts of the oral cavity. 

Suppose a mucinous plaque, from the surface of a tooth, is 
selected for study, and slide preparations are made, both fresh and 
stained, for examination. Examination of such stained prepara- 
tions will reveal the presence of long thread-like organisms, some 




Fig. 366. — From similar preparation to the preceding. Stained by Gram's 
method, m. Dense mass of micro-organisms from edges of which project : t. 
Thread forms; and B. Bacillus forms; N. Nucleus of partially-digested epithelial 
cell. 

stained in a homogeneous manner, others presenting small granules. 
Some of these are species of the genus leptothrix, others the genus 
cladothrix of the sheathed bacteria, while still others are members 
of the streptothrix group. Various types of rod-shaped organisms 
may be found, short and long rods, some grouped singly others in 
chains. Numerous types of spherical cells (cocci), some of which 
present a characteristic grouping, are always found. If fresh, moist 
material, either slide or hanging-drop preparation, is examined, some 
of the organisms will be found to possess the power of locomotion 
and move slowly or actively about the microscopic field. 
27 



4i8 



THE ORAL FLORA 



Preparations made from the alveolar sulci of unclean mouths, or 
from pathological conditions may contain bacteria of the same types 
as described above. In addition there will be found squamous 
epithelial cells in various stages of disintegration, some containing 
bacteria; mononuclear and polynuclear leucocytes, frequently 
present in sufficient numbers to constitute pus; other types of bac- 
teria, as fusiform bacilli, short and long chain streptococci; protozoa 
and various types of spirochseta or treponemata, which are readily 
recognised by the fact that they appear as long sinuously curved 




Fig. 367. — The scrapings from an approximal surface of a tooth. Shows all the 
typical forms found in the mouth. (Photomicrograph by Leon Williams.) 

rods pointed at the ends, and the Endamwba gingivalis recognised 
as a unicellular organism, many times the size of the largest coccus, 
circular or irregular in outline containing in the protoplasm granular 
debris, bacteria, other cells and one or more nucleus-like bodies. 
Examination of fresh moist preparations of such material will demon- 
strate the fact that some of the bacteria present are actively 
motile; the spirochaetae present a rapid sinuous or rotary movement, 
while the endamcebae move by means of pseudopods, producing the 
characteristic amoeboid motion. 
Preparations examined, microscopically, by aid of one or another 



ORAL MICROBIOLOGY 419 

of the dark field illuminators, in which the field is dark and the cells 
and other particles highly illuminated, will reveal the motile organ- 
isms moving about in various ways, some so characteristically as 
to enable the observer to establish their identity. This method of 
study will in many instances reveal the presence of organisms not 
readily demonstrated in stained preparations, notably certain 
flagellates the significance of which has not as yet been determined. 

Many expect a microbiologist to be able to identify and name the 
various species of micro-organisms, from their microscopic appear- 
ance; this is impossible excepting in a few instances. The identi- 
fication of a species is an entirely different proposition from iden- 
tifying a family or genus; species closely allied morphologically 
frequently show material differences when studied individually 
under appropriate conditions. 

For the purpose of identifying species it is absolutely essential, 
excepting in a few instances, that the organisms be isolated one 
from another in what is known as a pure culture, i.e., a culture 
which contains but one strain of a species. Individual organisms 
are identified by correlating the information obtained by observing 
the morphological characteristics; the mode of growth on various 
artificial media; the action on various proteins, carbohydrates, fats 
and other substances; the relation of growth to various physical 
conditions, such as oxygen and temperature relationships; pigment 
production and the determination of whether or not the organism 
is capable of producing disease. 

The methods of separating bacteria in pure cultures from mixtures 
containing different species, and methods employed in identifying 
those isolated, are dealt with in works on bacteriological technique; 
to which the student is referred for such information. 

PATHOGENIC ORGANISMS 

The following is a list of the most important pathogenic bacteria 
and other fungi encountered in the oral cavity: 

Micrococci: 

Micrococcus aureus. Synonym: Staphylococcus pyogenes 

aureus. 
Micrococcus albus. Synonym: Staphylococcus pyogenes albus. 
Micrococcus citreus. Synonym: Streptococcus pyogenes 

citreus. 



420 THE ORAL FLORA 

Diplococci: 

Micrococcus catarrhalis. 

Meningococcus. Synonym: Diplococcus intracellularis. 
Gonococcus. Synonym: Diplococcus gonorrhoeas. 
Pneumococcus. Synonym: Diplococcus pneumoniae. 
Tetracocci: 

Micrococcus tetragenus. Synonym: Sarcina tetragena. 
Streptococci: 

Hemolytic type. 

Streptococcus pyogenes. 
Streptococcus anginosus. 
Non-haemolytic type. 

Streptococcus viridans: Produces methaemoglobin. 
Streptococcus salivarius. 
Bacilli: 

Bacillus diphtheria?. Synonym: Bacterium diphtheriticum. 
Bacillus pseudo-diphtheria?. Synonym: Bacterium pseudo- 

diphtheriticum. 
Bacillus fusiformis. Synonym: Mycobacterium fusiforme. 
Bacillus tuberculosis. Synonym: Bacterium or Mycobacterium 

tuberculosum. 
Bacillus mallei. Glanders bacillus. 
Bacillus mucosus capsulatus. Synonym: Bacterium mucosum 

capsulatum. 
Bacillus inrluenziae. 
Bacillus anthracis. 
Bacillus acrogenes capsulatus. 
Bacillus tetani. 
Streptothricecz: 

Streptothrix bovis. Synonym: Streptothrix actinomyces, Ac- 
tinomyces bovis "The Ray fungus." 
Streptothrix hominis. 
Streptothrix buccalis. 
Spirochatce. Synonym: Treponemata. 

Spirochaeta pallida or Treponema pallidum. 
Spirochaeta vincenti or Treponema vincenti. 
Spirochaeta of the mouth, as Treponema macro- and micro- 
dentium and others. 
Higher Fungi: 

Ascomycetes. 
Blastomyces. 



ORAL MICROBIOLOGY 42 1 

Oidium albicans. 
Zygomycetes. 

Rhizopus nigrans. 
Sporothricum hominis. 
Protozoa: 

Sarcodina. 

Endamceba gingivalis. 
Flagellata. 

Trichomonas. (Significance questionable.) 

Spirochaeta or Treponemata. (See bacteria.) 

THE PYOGENIC COCCI 

Staphylococci pyogenetes, or Pyogenic micrococci. 

A. Micrococcus aureus or Staphylococcus pyogenes aureus. 

B. Micrococcus citreus or Staphylococcus pyogenes citreus. 

C. Micrococcus albus or Staphylococcus pyogenes albus. 

The presence of micrococci in pus was in all probability first 
demonstrated by Pasteur 1 in 1880. The first to isolate and establish 
the relation of the most important member of the group to suppura- 
tive processes was Rosenbach 2 in 1884, who called the organism 
Staphylococcus pyogenes aureus. 

This organism is widely distributed, being commonly found upon 
the external surface and in the oral and nasal cavities of man and 
many lower animals; it is not uncommonly found in the alimentary 
tract. When the tissue resistance is lowered, either locally, due to 
the action of some irritant; or generally, due to over-strain, malnu- 
trition or some constitutional disease, this organism frequently in- 
vades the tissues at a point of least resistance, and produces either 
a circumscribed or diffused local infection. If the organism gains 
access to the circulatory system, from a localised infection, it is 
carried to various parts of the body giving rise to that type of general 
infection known as pyaemia. In some cases when the virulence of 
the organism is high, or the resistance of the infected individual is 
low, death may ensue within a short time and at autopsy no sup- 
purative lesions (abscesses) will be found, the picture being that of a 
typical septicaemia. The Micrococcus aureus is frequently as- 
sociated, as an important secondary invader, with lesions primarily 

1 Annales de Chimie et Physiologic 

2 Arc'niv fiir Klin. Cbirur., 1888. 



42 2 THE ORAL FLORA 

due to some other organism, as in processes originally caused by 
the Bacterium tuberculosum or the Streptothrix bovis. 

In the oral cavity this organism is encountered as the primary- 
factor in superficial suppurative processes: Phlegmonous inflamma- 
tion, localised abscesses, infections of the salivary glands, and in 
some cases of necrosis; also as a secondary invader in "pyorrhoea 
alveolaris;" in areas surrounding infected teeth; occasionally in 
apical and alveolar abscesses; in many cases of necrosis of the man- 
dible and maxillary bone; in tubercular and actinomycotic lesions. 

It is the organism almost constantly found in the peritonsillar 
abscess, that condition known ordinarily as " quinsy." Infections of 
the nasal cavity, antrum of Highmore and other accessory nasal 
sinuses and middle-ear infections, including mastoid disease, are not 
infrequently due primarily to the action of this organism. While the 
Micrococcus aureus and albus are the most common of the pyogenic 
organisms, the oral infections due to their action constitute but a 
very small percentage of all infections of the oral cavity. 

The toxicity of Micrococcus aureus is due to an endotoxin; which 
endotoxin or another toxic substance produced by the organism 
(bacterial protein of Buchner) exerts a positive chemotactic action, 
i.e. , has the property of attracting leucocytes and producing pus. The 
phlogosine of Leber is probably identical with this substance; it also 
produces a leucocytotoxin known as a leucocydin. Some authors 
claim that the organism produces a soluble toxin, but from the fact 
that this so-called soluble toxin is only found in old cultures, one is led 
to consider it identical with the endotoxin, being liberated by the 
disintegration (autolysis) of the bacterial cells. The so-called 
haemolytic properties of this organism are not due, as some claim, to 
a haemolysin, but in all probability to the proteolytic enzyme pro- 
duced by the members of this group. 

It is of importance from a dental point of view, to note that the 
members of this group produce enzymes which have the property 
of acting on lactose, maltose, dextrose and certain other carbo- 
hydrates producing lactic, acetic and other mono-carboxylic fatty 
acids. 

Protective and Curative Inoculations 

Many attempts have been made to produce an anti-staphylo- 
coccus serum. Several such sera, obtained by inoculating animals 
with living and dead organisms and extracts of the bacterial cells, 
have been highly lauded by the investigators whose experimentation 



ORAL MICROBIOLOGY 423 

led to their production. But it is a pertinent fact that none of them 
have been employed to any extent as therapeutic measures. When 
one states that immunity against these organisms is essentially 
opsonic and agglutinative, the reason for the therapeutic failure is 
at once manifest. 

Bacterial vaccines, notably those prepared from that strain of the 
organism causing the infection, are of great value in treating and 
preventing the recurrence of infections due to the organisms of this 
group. 

The infections in which the Micrococcus albus is found, either as a 
primary cause or a secondary invader, are rarely as severe as those in 
which the Micrococcus aureus is the causative agent. The action of 
this organism is of the same nature, and due to the same type of 
toxic agents, as that of the aureus; rarely is its virulence nearly so 
great as that of the latter. The albus is constantly found in acne 
vulgaris; frequently as a secondary invader of various other condi- 
tions; often in association with the aureus. 

One strain of this organism, the Staphylococcus epidermidis albus 
of Welch, is found in the superficial layers of the skin, notably in the 
follicles, and has been demonstrated to be the causative factor in a 
large percentage of stitch abscesses. 

Micrococcus albus vaccines are of value in treating localized infec- 
tions caused by this organism. 

The third member of this group, the Micrococcus citreus, so-called 
from the fact that in its growth on artificial media a lemon-yellow 
pigment is produced, is not so commonly encountered as the aureus 
and albus; some authors claim it to be non-virulent, while others 
make no mention of this organism when dealing with the group. 

The degree of virulence of the citreus is as a rule about the same as 
the albus. Occasionally strains will be found possessed of a very 
high pathogenicity: such strains have been isolated from cases of 
pyaemia and carbunculosis. Citreus vaccines are employed in 
treating local infections caused by this organism. 

Micrococcus Catarrhalis. — This organism is not infrequently found 
in the oral and nasal cavities of normal individuals. It is encoun- 
tered in a small percentage of all cases of catarrhal inflammation of 
the oral and nasal mucous membranes; in some instances it 
has been found in groups of individuals presenting catarrhal 
infections; it has also been isolated from cases of bronchitis, pneu- 
monia, and other infections of the mucous membranes. The 
pathogenic properties of this organism are not marked, and its ac- 



424 THE ORAL FLORA 

tion in other than mild catarrhal conditions is usually that of a 
secondary invader, probably having little to do with the patho- 
logical process. The gingival trough is a normal habitat for this 
organism. (See Vol. i, p. 221.) 

In discharges from the oral and nasal mucous membranes the 
organism appears as a diplococcus, or singly and in groups, in the 
strands of mucus and fibrin, overlying the epithelial cells; and not 
infrequently within the protoplasm of the leucocytes. This fact has 
led to some confusion in differentiating this organism from the Menin- 
gococcus and Gonococcus, which is inexcusable in spite of the fact that 
they are all Gram negative, for the cultural and biochemical charac- 
teristics will readily enable one to differentiate between the Menin- 
gococcus and the Catarrhalis, and the fact that the Gonococcus will 
only grow on special media, renders the elimination of the latter 
organism comparatively easy. 

The action of the Micrococcus catarrhalis is apparently due to the 
production of an endotoxin. Vaccines have been employed in 
treating conditions apparently due to this organism, but the unusu- 
ally mild and acute character of the infections make it impossible 
for one to determine whether or not they are of any value. 

Meningococcus. — This organism, discovered by Weichselbaum 1 
and called the Diplococcus intraccllularis meningitidis, is the cause of 
the infection known as epidemic cerebro-spinal meningitis. The 
latter term is in a sense an unfortunate one, as other organisms are 
capable of producing meningitis of an epidemic character. 

The organism is spherical, occurring in pairs, usually within the 
polymorphonuclear leucocytes (pus cells), and is Gram negative, 
which makes it imperative to exclude Gonococcus and Catarrhalis 
infections when making a diagnosis. As stated when considering the 
Micrococcus catarrhalis this differentiation should not be difficult. 

The organisms gain access to the tissues by way of the oral and 
nasal cavities, and the meningeal symptoms are preceded by naso- 
pharyngeal symptoms, which may be manifest as a slight catarrhal 
disturbance or as a marked coryza and sore throat. An important 
fact to be noted is, that the organisms may lodge in sulci and crypts in 
the nasal and oral cavities, notably in the posterior nares, of healthy 
individuals; the latter constituting the so-called carriers, are mani- 
festly an important factor in disseminating the disease. 

Gonococcus. — This organism, the Diplococcus of Xeisser, is the 
cause of gonorrhceal infection, usually affecting the urethral mucous 
1 Grundriss der Pathologischen Histologic 



ORAL MICROBIOLOGY 425 

membrane in the male and the vagina and urethra in the female. 
The disease is readily transmissible to very few species of the lower 
animals. Infection of the eye, notably in infants {Ophthalmia 
neonatorum) is not uncommon. Nasal and oral infections are, on 
the contrary not frequently encountered; but when present it is 
manifestly of great importance that they be recognised. 

The organism exerts a marked pyogenic action which becomes 
manifest as a severe inflammatory reaction of the mucous mem- 
branes, accompanied by a profuse discharge of a purulent exudate. 
In this exudate the micrococci will be found as diplococci, usually 
flattened on one side, within the pus cells. They are Gram negative, 
which fact aids materially in differentiating them from the ordinary 
pyogenic cocci. They can be isolated only by means of special 
media, these rendering their differentiation from the Meningococcus 
and Catarrhalis a matter of not more than twenty-four hours. 

The Streptococci 

From a dental point of view no single species or group of organ- 
isms, is of greater importance than the streptococci. 

The older investigators divided the streptococci into the Strepto- 
coccus longior et brevior or Streptococcus longus and brevis, accord- 
ing to their occurrence in long or short chains. The fact was recog- 
nised that the organisms found grouped in long chains were possessed 
of the higher degree of virulence. Among these were classed the 
Streptococcus pyogenes, Streptococcus erysipelatus, which organism we 
now recognise as not being any different from the pyogenes, and 
Streptococcus conglomeratus , which is simply a strain of the pyogenes 
growing in conglomerate masses of closely intertwined chains. At 
this time that strain known as Streptococcus anginosus was not dif- 
ferentiated from the pyogenes. It is important to note that the 
above types have the property of haemolysing erythrocytes, which 
fact has led to their being called the Hemolytic streptococci. 

The short chain streptococci include the organisms known as 
Streptococcus viridans, Streptococcus mitis, Steptococcus jcccalis, 
Streptococcus saliavarius and others. 

Some strains of this latter group are of great importance to the 
dental practitioner; the most important, the Streptococcus viridans, 
being found in at least go per cent, of the oral cavities of human 
beings. 

Some group with the streptococci the Pneumococcus and that 



426 THE ORAL FLORA 

strain of the organism known as Streptococcus mucosus capsidatus. 
From certain viewpoints this is of advantage, notably when making 
isolations and group differentiations. 

Owing to the dental importance of some members of the group we 
consider the subject of sufficient importance to admit of our discus- 
sing the group differentiation before taking up the properties of the 
various organisms. 

Streptococci grouping and methods of differentiation have been 
subjects of discussion and investigation for twenty years, the de- 
tails of which will be found in works on the subject of pathological 
bacteriology. 

The methods of differentiation are based principally upon the 
morphological and biochemical features. In connection with the 
former, such characteristics as the type of chain formation and 
whether or not capsules are produced; as regards the latter, the 
action on various carbohydrates, on haemoglobin, and the effect of 
bile on the life and growth of the organism. Within the last few 
years differentiation by the complement-fixation and agglutination 
reactions have aided in separating these organisms. 

In discussing this phase of the subject, we will assume that several 
organisms have been isolated and studied as regards their ordinary 
morphological characteristics, cultural and biochemical features. On 
making such studies, one is forcibly impressed by the marked simi- 
larity of the various cultures. One group will not ferment lactose: 
the type of this group is Streptococcus equinus. 

The next proceeding will be to culture the organisms fermenting 
lactose in a medium (sugar-free broth or serum water) containing 
i per cent, of inulin. If the medium is fermented, the organism is 
a member of the Pneumococcus group. This can be confirmed by 
culturing in bile medium. The various strains of the pneumococcus 
being bile-soluble, are destroyed, while the streptococci will develop 
luxuriantly. 

The organisms of the group incapable of fermenting inulin and 
not bile soluble, namely the Streptococci, are cultured in blood-agar 
plates, when the type of reaction admits of their being separated 
into three groups: (i) Those hsemolysing erythrocytes, which phe- 
nomenon is manifest by the appearance of a clear zone surrounding 
the colonies; these are the Hcemolytic streptococci; (2) Those pro- 
ducing methaemoglobin, which reaction is manifest by the appear- 
ance of a greenish colouration of the colony and a greenish zone in the 
medium immediately surrounding it; this group includes the Strep- 



ORAL MICROBIOLOGY 427 

tococcus viridans and the Streptococcus salivarius; (3) Those exert- 
ing no action on haemoglobin or erythrocytes, as the Streptococcus 
j'cecalis and Streptococcus lactis. 

The organisms of the hemolytic type may be differentiated by 
culturing in a broth or serum-water medium containing the glucoside 
salicin; the ones fermenting salicin, with acid production are strains 
of the Streptococcus pyogenes, those not fermenting salicin the Strep- 
tococcus anginosus. 

Of the group producing methaemoglobin, the Streptococcus viridans 
ferments salicin while the Streptococcus salivarius does not. The 
Streptococcus facalis, of the indifferent group, ferments the glucoside 
and the Streptococcus lactis reacts negatively. 

Streptococcus Pyogenes. — This organism is spherical in form and 
found grouped in long chains. Such chains are always manifest when 
preparations made direct from pathological lesions are examined, and 
usually in cultures, especially when" cultured in liquid medium or in 
the water of condensation of blood-serum or agar slants (Fig. 368). 

This organism is found as the primary invader in a variety of 
local infections, some circumscribed, others diffuse as in erysipelas, 
and not infrequently as a secondary invader in processes primarily 
due to some other organism. 

It is the type usually found in the septicaemia following child- 
birth (puerperal septicaemia), in which case the organism gaining 
access to the uterus, by way of the vagina, is absorbed and carried 
to various parts of the body. When this organism gains access to 
the general circulation from a localised infection (focal infection), 
the resulting septicaemia is generally of a fulminating character, 
causing death within a comparatively short time; some few cases 
recover. Cultivation on artificial media quickly reduces the viru- 
lence of this organism. On the other hand, the virulence may be 
greatly enhanced by passage through animals, notably rabbits, and 
undoubtedly the same increase in virulence is true of organisms 
developing in acute infectious processes. 

This organism is the one usually concerned in follicular tonsillitis, 
in some acute gingival and buccal infections, occasionally in infec- 
tions of the salivary glands and diffuse cellulitis of the oral tissues. 
In a certain percentage of the cases of that symptom complex known 
as Ludwig's angina the Streptococcus pyogenes is found; it is en- 
countered in some cases of necrosis of the mandible and maxilla; 
and also in a certain percentage of antral and frontal sinus infections. 
Contrary to the statements occasionally made to the effect that this 



428 



THE ORAL FLORA 



organism is common in apical abscesses, it is but rarely found in 
either apical or alveolar abscesses. Neither is it commonly found 
in "pyorrhoea alveolaris." 

This organism may be the sole cause of pneumonia and not in- 
frequently secondarily invades the lung in cases of pneumococcus 
pneumonia. It also frequently plays an important part by secondarily 
invading a pulmonary tubercular abscess, in that it adds to the toxae- 
mic condition and induces the breaking down of tissue leading to 
cavity formation. 

The toxic products of the organism are, an endotoxin, a soluble 
toxin, and a hemolysin. 






/ 



Fig. 368. — Streptococcus longus (pyogenes), from a fatal case of pyaemia. Mag- 
nified 1,000 times. (Trans. Odonto. Soc. of Great Britain.) 

Anti-streptococcus sera of various types have been employed in 
treating different types of streptococcus infection. On the whole the 
results have been extremely disappointing. Autogenous strepto- 
coccus vaccines are of value in treating certain acute and subacute 
infections. They may be employed in general infections, but the 
results obtained are not of such a nature as to cause one to consider 
them among the important therapeutic measures. The so-called 
stock polyvalent streptococcus vaccines are, in the writer's opinion, 
of absolutely no value. 

Streptococcus anginosus. — This organism is closely related to the 
Streptococcus pyogenes, occurring in the same long chains, exerting 
a haemolytic action, but differing from it in the fact that salicin is 



ORAL MICROBIOLOGY 



429 



not fermented. As a rule it causes coagulation in milk. The latter 
feature however is not constant. 

This strain is found in a large percentage of cases of so-called epi- 
demic septic sore throat, and is also encountered as a secondary 
invader in many cases of scarlet fever. Extensive epidemics of 
septic sore throat have been reported from time to time in various 
countries, and in America numerous epidemics have occurred. 
This type of sore throat, affecting the fauces and tonsils, is very 
severe and accompanied by marked constitutional symptoms, at 
times due to toxaemia. In other cases, in addition to this, the organism 
invades the tissues via the circulation, producing a septicaemia 




Fig. 369. — Streptococcus brevis, from a healthy mouth. Magnified 1,000 times. 
{Trans. Odonto. Soc. of Great Britain.) 



which has resulted in a comparatively high percentage of deaths. 
The organism giving rise to the epidemic may be disseminated by 
means of milk from cows affected with mastitis; or by individuals 
who are infected with the organism handling the milk, or receptacles 
in which it is collected and distributed; in other epidemics the organ- 
isms are evidently disseminated in some other manner. 

Vaccines and sera are of little or no value in treating this infection. 

Streptococcus Viridans. — This name is applied to that short chain 
streptococcus producing methaemoglobin when cultured in blood 
media, and fermenting salicin with acid formation. 

This organism is constantly encountered in the oral cavity, not 



43° THE ORAL FLORA 

only in pathological conditions but also in healthy individuals, even 
of those who exercise great care in cleansing their mouths (Fig. 369). 

It is encountered as the primary cause or as a secondary invader 
in the majority of oral infections, in fact in practically all superficial 
infections. In some cases its presence is of no moment, in others it 
has a marked detrimental action on the tissues. The presence of 
this organism in apical abscesses is almost constant, and it is found 
in a great percentage of alveolar abscesses. In many cases of antral 
and frontal sinus infections the viridans is encountered either alone 
or in association with some other organism. Manifestly it is 
present in many cases of necrosis. 

When this organism gains access to the circulation from a focal 
infection it is carried to all parts of the body. It rarely possesses a 
marked degree of virulence and therefore does not often give rise 
to a fulminating, but rather to a low-grade septicaemia. In many 
cases when it is disseminated throughout the body, the pathological 
action is not manifest as a general infection but localised in one part, 
and such conditions as arthritis, synovitis, neuritis, endocarditis, etc., 
arise. Very often clearing up of the focal infections leads to 
the disappearance of all symptoms. The reason for this is mani- 
fest; the organism possesses a low degree of virulence and the bodily 
defenses are enabled to prevent a general action on the tissues. 
Many of the organisms are destroyed; those remaining in a locality 
of lowered resistance are enabled to develop and exert a detrimental 
action on the tissues. In many cases when these organisms produce 
a low-grade septicaemia, the condition may be cured or may lead to 
the death of the patient after a somewhat prolonged illness. 

Streptococcus Salivarius. — This strain of the short chain strepto- 
cocci may be encountered in the same type of infection as the 
viridans; it is however, as a rule possessed of but a very low degree 
of pathogenicity. 

Pneumococcus or Diplococcus Pneumonia.- — -This organism in cul- 
tures cannot always be differentiated readily from the short chain 
streptococci, as it frequently occurs in short chains and reacts 
culturally in about the same manner. The various types of this 
organism ferment lactose and inulin: all are bile soluble. Within the 
last few years various types have been separated; types differing one 
from the other sufficiently to admit of their being differentiated 
biologically; pathologically their action is much the same. For 
information on this and the general phases of pneumococcus infec- 



ORAL MICROBIOLOGY 43 1 

tion, the student is referred to recent works on pathological 
bacteriology. 

When stained by appropriate methods in sputum, catarrhal 
exudates, pus, blood and tissue fluids, the organism appears as a 
diplococcus surrounded by a definite capsule. At times three or 
four elements will be enclosed in one capsule; one type called the 
Streptococcus mncosus capsulatiis occurs in long chains surrounded by 
a distinct capsule. 

The Pnenmococcus is not infrequently found in the oral cavities 
of healthy individuals; therefore one might expect to find it in vari- 
ous pathological conditions. In some cases of ulcerative stomatitis, 
in which there are present small, often painful, superficial ulcers, the 
pneumococcus is present as the primary infective agent; it is found 
in many cases of "pyorrhoea" and other gingival infections. If alveo- 
lar abscesses be detected soon after their formation and proper pre- 
cautions be taken in opening and examining their contents, the 
pneumococcus will be frequently found in pure culture; it is however, 
rarely found in apical abscesses. Occasionally the pneumococcus in 
association with streptococci and other organisms, is encountered in 
necrosis. Not infrequently it is found in antral infections. Should 
the organism gain entrance to the general circulation, a pneumococcus 
septicaemia may result. There are on record cases of pneumococcus 
meningitis; in some of these cases the organisms in all probability 
gain access to the cranial cavity by way of the nose or naso-pharynx. 

This organism has been demonstrated in not a few cases of acute 
catarrhal infection of the upper air passages as apparently the only 
organism present capable of causing such infection. Pneumococcus 
conjunctivitis is a well-recognised infection. 

Bacillus diphtheria?, or more properly speaking, Bacterium or 
Mycobacterium diphtheriticum, the cause of the disease known as 
diphtheria, is occasionally encountered in infections of the oral 
mucous membrane. The fact that such infections are not more 
common is somewhat surprising when one considers the frequency 
of diphtheritic infection of the tonsils and pharynx. 

This organism occurs in the form of short or long rods presenting 
clavate or cuneate swellings. In stained preparations the proto- 
plasm, instead of appearing homogeneous or finely granular, is 
barred or striated, in many cases containing metachromatic granules 
which, when stained by appropriate methods, assume a colour 
different from the other constituents of the cell, indicating that chem- 
ically they are of a different nature from the rest of the protoplasm. 



432 THE ORAL FLORA 

When a given strain of this organism is cultivated on various kinds of 
media and examined, one is forcibly impressed with the marked 
variations in morphology exhibited; variations in the reaction of the 
medium: presence of substances exerting a detrimental action on the 
organism. Hypo- or hypertonicity seem to be the determining factors 
in these morphological variations. The bizarre forms are known as 
involution forms; under certain conditions of cultivation the organ- 
isms present buds and not infrequently short and long branches 
which branches are frequently swollen at the ends. 

The pathogenic action of the organism is due solely to a soluble 
toxin; as a means of combating diphtheritic infection an antitoxic 
serum is employed. 

From a dental viewpoint it is of importance to note that healthy 
individuals may be carriers, the organism developing in the crypts 
of the tonsils and sulci in the naso-pharynx. 

There are several types of organisms morphologically like the 
Mycobacterium diphtheriticum, which are frequently encountered in 
the oral cavity, some colourless, others producing coloured growths on 
artificial media. These are grouped under the general term of pseudo- 
diphtheritic organisms. Pathologically from our viewpoint they are of 
very little import. Some strains may be concerned in mild catarrhal 
conditions of the oral and nasal mucous membranes. The chromo- 
genic types are commonly found in milk. 

The import of this group rests on the fact that they resemble the 
diphtheria organism morphologically, and, to a great extent, cul- 
turally, and must be differentiated from the latter in suspicious cases. 
In no case do they induce infection in any manner resembling 
diphtheria. 

Bacillus tuberculosis, or Mycobacterium tuberculosis, is the cause of 
the various tubercular infections as: pulmonary tuberculosis, general 
miliary tuberculosis, glandular tuberculosis, tuberculosis of the 
skin, etc. This organism is one of the few that can be readily and 
positively diagnosed in stained preparations of sputum, pus, etc., 
the diagnosis depending on the fact that one of the constituents of 
the cell of the organism is a peculiar wax which gives to it " acid-fast " 
or acid-resisting properties. It stains with difficulty, but when once 
stained, retains the stain tenaciously, resisting to a marked degree the 
action of decolourising agents. Therefore when material is stained 
with an intense red dye such as carbo-fuchsin; treated with decolour- 
ising agents such as 30 per cent, nitric acid, 5 per cent, sulphuric acid 
or acid alcohol; washed and counter-stained with methylene blue, the 



ORAL MICROBIOLOGY 433 

presence of the B. tuberculosis is indicated by the finding of red rods, 
straight or curved, usually beaded, in a field, all other elements of 
which are stained blue. 

Tubercular infections are of great importance to the dental prac- 
titioner. In the first place in pulmonary tuberculosis the organisms 
are present in the sputum, and manifestly in the oral cavity. Tuber- 
cular infections of the tonsils and oral mucous membrane are not 
common but are occasionally encauntered. (See page 355) . Tuber- 
cular infection of the salivary glands are occasionally seen, as is tuber- 
cular caries of the mandible and tubercular antral infections. One 
type of tubercular infection, the lesions of which are not infrequently 
mistaken by the dentist as being due to syphilitic infection, is that 
condition of the nose and face commonly known as Lupus vulgaris. 
Not infrequently this results in a destruction of tissue to such an 
extent as to cause marked disfigurement, not only by destroying the 
soft tissue of the nose but bony tissue as well. In all of these con- 
ditions the organism may be readily demonstrated in the tissue by 
appropriate methods of staining. 

Bacillus Mallei, Glanders Bacillus, or Mycobacterium Mallei, is the 
causative agent in the disease known as glanders. This disease is 
primarily a disease of horses, mules and asses, but is occasionally 
transmitted to other domestic animals and man. There has been 
much discussion as to the portal of entrance of the organism, but 
undoubtedly in a certain percentage of cases, it gains access by way of 
the nasal and oral orifices. 

Veterinarians, hostlers and others coming in contact with horses 
are most often infected, and present oral and nasal inflammatory 
lesions due to the action of this organism. 

Bacillus anthracis or Bacterium anthracis is a rod-shaped organism, 
non-motile, occurring in chains and forming endospores. It is the 
causative agent in the disease known as Anthrax, Charbon, or Malig- 
nant pustule. This infection, primarily a disease of cattle and sheep, 
may be transmitted to man. The organism enters the tissue through 
an abrasion, or by way of the nasal and oral cavities, being taken into 
the lungs with dust, and into the intestinal tract with food and 
drink. It produces a marked cedematous inflammation at the 
point of entrance, and fulminating septicaemia when, after gaining 
access to the circulation, the organisms are carried to all parts 
of the body. The pulmonary type of anthrax infection is fre- 
quently called " wool-sorter's disease." 

Bacillus mucosus capsulatus, Friedlander' s bacillus, or the Bac- 
28 



434 THE ORAL FLORA 

terium mucosum capsulatam is a capsulated, non-motile, rod-shaped 
organism which does not form endospores. 

Classed under this group are several types varying not at all 
morphologically and but very little culturally. They are differen- 
tiated one from the other essentially by their action on certain carbo- 
hydrates. One type, the B. rhinoscleroniatus, is found in the 
disease known as rhinoscleroma; a second, the B. wzence, occurs quite 
constantly in cases of foetid catarrhal inflammation of the nose. 
The Bacterium mucosum capsidatum is very frequently encountered 
in the oral cavities of healthy individuals; it exists also in a variety 
of pathological conditions, probably rarely as a primary cause, 
but rather as secondary invader. Some claim that this organism is 
the cause of scleroma lingua. 

Bacillus aerogenes capsulatus, the so-called gas bacillus of Welch 
is found in the intestinal tract of man and lower animals. This 
organism is the cause of gas gangrene, the gas production being due 
to its ability to split up complex substances, notably carbohydrates, 
with the formation of simpler compounds, among which are certain 
gases. 

This same organism has been described by various authors who 
apparently knew nothing of the work of Welch. The Bacillus pcr- 
jringcns, the Bacillus of Glum and Sachs, Bacillus phlegmonous 
emphysematosa of Fraenkel and others are identical with the bacillus 
of Welch. 

This organism is a strict anaerobe, occurs singly and in chains. 
When found in the tissues and stained appropriately, it always pre- 
sents a distinct capsule. It is non-motile, forms endospores and 
reacts positively to Gram's stain. Its natural habitat is evidently 
the soil. This organism has been encountered not only in the oral 
cavities of normal individuals, but in pathological conditions where 
individuals have extensive injuries to the face and oral tissues, 
notably when soil and excrementitious substances contaminate the 
wounds. The danger of such infection should be realized and 
proper precautions taken against such untoward complications 
occurring. 

It has been claimed that Miller first discovered this organism as 
existing in the oral cavity. 

Bacillus Tetani. — This organism, a strictly anaerobic, spore-form- 
ing motile rod, is the cause of the disease known as tetanus, fre- 
quently called "lockjaw." 

While tetanic spasm of the jaws is a prominent symptom of this 



ORAL MICROBIOLOGY 



435 



disease it is rare to find the focus of invasion in the oral cavity, al- 
though the organism is undoubtedly frequently present here as 
well as in the intestinal tract of healthy individuals. 

This organism is constantly encountered in the soil in some loca- 
lities, and gains access to the tissues through wounds, developing at 
the point of invasion, producing a soluble toxin which is carried 
throughout the tissues by the circulation, the organism remaining 
at the local lesion. 

There are other anaerobic organisms found in the soil which may 
be found in the oral cavity. Some are pathogenic but, rarely, if 




Fig. 370. — Streplothrix actinomyces. From section of a tongue of an ox. 
Stained by Gram's method, counterstained with eosme. Magnified 800 times. 
c. Club-shaped forms. 



ever, concerned in oral infections. Some are organisms of the 
malignant oedema type, others, while not of a pathogenic nature, 
may play an important role in dental caries. 

Streplothrix bovis, variously known as Streplothrix actinomyces, 
Actinomyces bovis, Discomyces bovis, the Ray fungus, occurs as long 
thread-like, interlacing filaments, presenting a true branching and at 
times, small spherical bodies, the true significance of which is still 
a mooted question, some writers claiming they are spores or conidia 
and others denying this. 



43 6 



THE OSAL FLORA 




Fig. 371. — The same. From a culture. Magnified 800 times. 




Fig. 372. — Cladolhrix'dicholoma. Stained by Gram's method. Magnified 800 

times. 



ORAL MICROBIOLOGY 



437 



When examining pus, sputum, and the tissues of infected animals, 
small yellowish or whitish opaque granules will be found, usually 
about the size of a millet seed. If these granules are crushed, 
stained and examined microscopically, the organism will be readily 
demonstrated as long entangled branched filaments, usually termi- 
nating in bulbous ends (clubbed). These filaments in general 
arrangement radiating from the centre give rise to a radiate mass 
which led to the organism being called the "ray fungus." In 
tissue sections the radiate colonies are readily demonstrated. 

This organism is the cause of " lump-jaw " and " wooden tongue" 
or actinomycosis of cattle, but while it is frequently localised in the 




Fig. 373. — Cladolhrix from mouth direct. Stained by Gram's method, 
nified 1.000 times. (Trans. Qdonto. Soc. of Great Britain.) 



Mag- 



mandible, the organism in many cases invades the other tissues. 
In man, oral actinomycosis is occasionally encountered, not only 
as lesions of the mandible and maxilla, but the soft tissues as well, 
notably the tongue. 

The name Streptothrix hominis has been given to some organisms 
of this group from human sources. Whether or not this is a type 
different from the bovis is an open question. One type found not 
infrequently in the oral cavity has been named the Streptothrix bitc- 
calis. This organism is encountered in apparently healthy indi- 
viduals, usually those whose mouths are not kept clean. It has 
been encountered in the tonsillar crypts, in the so-called mycosis of 
the tonsils; and in deep tonsillar lesions. Similar organisms have 



438 THE ORAL FLORA 

been found in a few of those cases of chronic bronchitis in which 
there is a very profuse expectoration of a muco-purulent material 
(bronchorrhcea). 

Members of the streptothrix group have frequently been mistaken 
for the Cladothrix dichotoma, an organism belonging to the genus 
Cladothrix or Sphcerotilus of the family of Chlamydobactcriaceae. 
Their cultural characteristics are similar; but by appropriate 
methods of staining, the latter organism will be found to present 
a distinct sheath and the apparent branching to be not a true, 
but a false branching. This organism is occasionally found in the 
oral cavity but is of no pathological significance (Fig. 373). 




Fig. 374- — Cladothrix. Forty-eight hours - cultivation in agar. Magnified 500 
times. (Trans. Odonlo. Soc. of Great Britain.) 

Bacillus fusiformis or Mycobacterium fusiformi was first dis- 
covered by Vincent in cases of hospital gangrene. This organism 
is .almost invariably associated in pathological conditions with the 
Spirochcela vincenti (Treponema vincenti). Both are anaerobic 
organisms and are difficult to isolate, but may be readily demon- 
strated in the exudate from pathological conditions in which they 
are present, making a diagnosis not difficult. Some claim that they 
are but pleomorphic forms of one organism. This view, however, can- 
not be accepted. The Bacillus fusiformis is a non-motile, rod-shaped 
organism, slightly enlarged in the middle and pointed at the ends. 
The Treponema vincenti is a long slender, curved, wavy or sinuous 
organism somewhat thickened at the middle and gradually taper- 



ORAL MICROBIOLOGY 439 

ing out to a thin flagella-like filament at the ends. When examined 
under dark field illumination the organism will be found to present 
active sinuous and wavy movements. 

These organisms are constantly found in that tonsillar infection 
known as Vincent's angina; in certain types of localised and spreading 
ulcerative stomatitis (especially along the gingival border) ; in many 
cases of "pyorrhoea alveolaris;" in some cases of that diffuse cellulitis 
of the floor of the mouth, frequently called Ludwig's angina (Angina 
Ludovici) ; occasionally in infections of the salivary glands, notably 
the submaxillary and sublingual; constantly in gangrenous stoma- 
titis or noma (Cancrum oris). The infection called " trench mouth " 
is an ulcerative stomatitis, the causative agents of which are the 
Bacillus fusiformis and the Treponema vincenti. Infections due to 
these organisms occur in various other parts of the body. 

Spirochceta pallida or Treponema pallidum, the specific infective 
agent of syphilis, will be found in the primary and secondary oral 
lesions of syphilis, when material from the lesions, carefully obtained, 
is examined by dark field illumination or in preparations stained by 
special methods. 

Under dark field illumination it is seen as a spirally curved organ- 
ism turning rapidly upon itself and presenting a rotary and sinuous 
movement. 

When stained by appropriate methods the organism appears as 
spiral cells from 8 to 14 fj. in length, tapering to a slender flagella- 
like extremity at each end. The turns of the spiral are close and 
regular. It cannot be demonstrated by the ordinary methods of stain- 
ing; other spirochaetes have been mistaken for the pallida, but the 
danger of one who has had some experience of making such an error is 
slight, the other types varying in size, form and arrangement of the 
spirals to such an extent as to render their elimination an easy 
matter. Several spirochaetes have been described as frequently 
occurring in the mouth, one author, basing his contention on morpho- 
logical grounds alone, separated them into eight species. This is un- 
doubtedly erroneous. The Treponema microdenlium, formerly called 
Spirochete dentium, and the Treponema macrodentinm, formerly 
called the Spirochete buccalis and the Treponema vincenti are the 
ones most commonly found. They are readily demonstrated in 
stained preparations. 

Oidium Albicans — Saccharomyces Albicans or Endomyces Albi- 
cans.— This organism belongs to the same group of cryptogams as 



44Q 



THE ORAL FLORA 



the yeasts, namely the Eumycetes or true fungi, order of Asco- 
mycetes. The oidium evidently belongs to the family Endomyces. 

This organism is the cause of mycotic stomatitis, the condition 
variously known as "thrush." Some have called the condition 
oidiomycosis, rather unfortunately, as this name has also been 
applied to blastomycotic dermatitis. 

If a small particle of one of the characteristic milk white, friable 
patches from the oral mucous membrane be spread upon a slide, 
stained and examined, long filaments, septated into oval or rod- 
shaped elements, will be found. There are frequently present numer- 
ous spherical or oval bodies, often containing a smaller spherical 
body, known as the ascospore. 




FlG. 375. — Oidium albicans. From a culture. Magnified 600 times. 



Several kinds of Yeasts have been encountered in oral infections. 
Whether or not they are distinct types is a question, as the descrip- 
tions given are not sufficiently complete to admit of absolute differ- 
entiation. From the similarity of the lesions produced, the majority 
are undoubtedly identical with the Blastomyces dermatidis of Gil- 
christ, first found in a peculiar type of chronic dermatitis. This 
organism is occasionally encountered in a chronic ulcero-granulo- 
matous condition of the oral tissues, which has in some cases 
been mistaken for carcinoma until a microscopic examination cleared 
up the diagnosis. In the tissues the organism appears as oval or 
spherical cells, averaging from 10 to 12 n in diameter; the 



ORAL MICROBIOLOGY 44 1 

majority of the cells being about 5 n in diameter, while some 
elements are much larger. 

The cell, by appropriate methods of staining, presents a thick 
membrane surrounding the central protoplasm. These cells not in- 
frequently, owing to the fact that they multiply by budding at least 
in one stage of their development, occur in pairs of unequal size. 

A Yeast, the Saccharomyces nigrans, has been found in some cases 
of Lingua nigra or black tongue. When examined microscopically 
the cells appear as small oval bodies, occurring singly and in pairs. 
Occasionally three will be grouped together; one cell, the parent cell, 
will be larger, the attached cells smaller than those occurring singly. 
In cultures this organism produces a black pigment. The organism 
commonly found in the mycotic type of Lingua; nigra is however not 
a yeast but the Rhozopus nigrans, a black mould closely related to, 
some claim identical with, the Mucor nigrans. In stained prepara- 
tions this organism may be demonstrated among the epithelial 
cells as long filaments septate and often branched. At times the 
characteristic oval or round spores will be found in such preparations. 

Sporothrix Infections. — The organisms causing the so-called 
Sporothricosis apparently belong to the Ascomycetacece; the type 
organism is the Sporothrix schencki. This organism invades the 
tissues at some local point, usually where their resistance has 
been lowered, and gives rise to peculiar hard, indurated sub- 
cutaneous and submucous lesions in man. These lesions frequently 
break down and abscesses are formed which are usually chronic. 
The organism may invade the buccal, pharyngeal and laryngeal 
mucous membranes. In the purulent exudate the organism is 
found among the pus cells as yeast-like cells, oval and fusiform in 
character; at times a filament will be found with groups of the oval 
bodies (spores) arranged about the end. The organism is readily 
isolated and cultivated on artificial media. In such cultures the 
morphological characteristics of the organism vary quite markedly 
from the characteristics of the organism as found in the tissues. 

THE FILTERABLE VIRUSES 

There are certain diseases having all the characteristics of infec- 
tions, in which all attempts made at isolating the causative agents 
or even demonstrating such agents microscopically, have met with 
failure. Further investigation demonstrated the fact that when 
the material, macerated and diluted, was passed through a so-called 



44- THE ORAL FLORA 

germ-proof filter, the filtrate when injected into suitable animals 
gave rise to the same type of infection as that in which the original 
material was found. Several such infections exist, of which the one 
of most importance to the dentist is "foot-and-mouth disease," or 
aphthous fever. While primarily a disease of cattle, sheep, goats, 
and pigs, the infective agent, during epidemics, not infrequently 
gains access to the oral cavities of human beings directly from in- 
fected animals, infected milk, etc., and causes a severe aphthous 
inflammation. 

Endamceba Gingivalis (Gros). — This protozoon was first described 
by Gros in 1849, and named Amoeba gingivalis; since then it has 
been observed by others and variously named Amoeba buccalis, 
Amoeba dentalis and Entamoeba buccalis (Fig. 376). 

The organism was frequently observed in microscopic preparations 
from dirty mouths, pyorrhceal infections, etc. However no patholog- 
ical significance was attached to its presence until Smith and Barrett, 1 
after a study of a group of cases of "Pyorrhoea alveolaris," announced 
the fact that the organism was found in a large percentage of cases of 
infected gingival tissues. They ascribed to it an important etiolo- 
gical relationship as regards pyorrhceal infections. 

The organism may be demonstrated in fresh preparations by mix- 
ing the material with a drop of salt solution on a warm slide, applying 
a cover glass and searching the slide for motile organisms with an 
8-mm. lens. The preparation must be kept warm, therefore the 
search is best made with a microscope fitted with a warm stage. 

The organism may also be readily demonstrated in dried prepara- 
tions by staining with appropriate stains, as Giemsa's method or 
with carbol-fuchsin followed by methylene-blue. 

In fresh preparations the Endamceba,, averaging about 30 n in 
diameter are quite actively motile, presenting an irregular outline, 
due to throwing out of pseudopodia. In the quiescent stage they are 
usually circular or oval, the ectoplasm is hyaline, while the endo- 
plasm is granular and usually contains bacteria, disintegrated ery- 
throcytes and leucocytes. The nucleus can rarely be seen in fresh 
preparations. Vacuoles are usually present, some empty while others 
contain inclusions of different sizes and shapes. When stained, 
the ectoplasm usually appears to be finely granular in structure; the 
endoplasm coarsely granular and frequently alveolated. Inclusions 
of various sizes and shapes are usually found within the endoplasm. 

^'The Protozoa of the Mouth in Relation to Pyorrhoea Alveolaris," "Dental 
Cosmos," Aug., 1914- 



ORAL MICROBIOLOGY 



443 



The nucleus is circular or oval with a centrally located chromatin 
mass. 

ADVENTITIOUS BACTERIA OF MOUTH 

There are other organisms found in material from the mouth which 
have not been encountered in any other place, although their original 
habitat is undoubtedly some place in nature, as soil, water, etc. 
Certain of these organisms are bacteria, others higher fungi; they 




Fig. 376. — Rndamceba gingivalis. a. Amoebae; l. Polymorphonuclear leucocyte. 
(Photomicrograph by courtesy of Dr. Percy R. Howe.) 

have been named and described by various early investigators, 
notably Miller, 1 and Vicentini, 2 later by Leon Williams 3 and Goadby. 4 

1 "Microorganisms of the Human Mouth," 1889. 

2 International Journal of Microscopy and Natural Science, 1894-95. 

3 "Contributions to the Bacteriology ofthe Human Mouth," Dental Cosmos, 
1899. 

4 ''Mycology of the Mouth," 1903. 



444 TH E ORAL FLORA 

Some of the organisms have bsen identified with others occurring 
more or less widely disseminated; others, owing to the fact that they 
were not described in sufficient detail cannot be recognised as dis- 
tinct species today. Some of these organisms are constantly en- 
countered in stained preparations from the mouth, notably in the 
case of individuals who do not exercise proper care in cleansing the 
oral cavity; also in the material which collects on the teeth during 
sleep, and in the so-called mucinous plaques (bacterial plaques) 
which form on the surface of the teeth. Such organisms are often 
found microscopically in many pathological conditions, not as causa- 
tive factors but as accidental contaminations. Some can only be 
recognised by their morphological characteristics, owing to the fact 
that they have resisted all attempts directed toward their isolation 
and study in artificial media. Possibly some have been isolated and 
are known under other names, it being a well-known fact that cer- 
tain organisms differ markedly in form under varying conditions of 
development, as it were in different phases of their life cycle. 

For the purpose of illustration, suppose we refer again to the micro- 
scopic study of material of various kinds from the oral cavity. The 
most important of the organisms concerned in pathological condi- 
tions are: various types of cocci, rod-shaped organisms, spiral and 
thread forms; these have been isolated and studied in cultures. There 
are others which are readily isolated which have no pathological 
significance, although they may play a part in dental caries. Among 
such organisms are the following: 

Sarcina alba, lutea and aurantica. — These develop readily on arti- 
ficial media, producing respectively no pigment, a yellow, and an 
orange pigment. They divide in three planes, the cells remaining 
approximated, resulting in the formation of cubical masses. These 
cocci are quite large, i to 1.5/x in diameter, non-motile, non-spore 
forming, and are positive to Gram's stain. 

Iodococcus vaginatus of Miller which he claimed is found in all 
unclean mouths occurs singly, or in short chains, and gives the iodine 
reaction. The identity of the organism has never been established: 
its importance is probably only historical. 

Micrococcus tetragenus or Sarcina tetragena is observed in oral 
material, appearing as small cocci from 0.6/u to o.8,u in diameter occur- 
ring in groups of four. This organism is at times noticed in 
pathological conditions as a secondary invader. 

Of the rod-shaped organisms encountered, those worthy of men- 



ORAL MICROBIOLOGY 



445 



tion, beside the pathogenic organisms already considered, are the 
following: 

Bacillus buccalis maximus, which presents as jointed threads 10 to 
50// long and 0.5 to r.5/1 wide, frequently straight, at times curved, 
positive to Gram's method. Flagella are present. Goadby has iso- 
lated and described an organism under this name which apparently 
belongs to the Mesentericus or Subtilis groups of the ordinary spore- 
forming soil organisms. Leptothrix buccalis of Vignal' and Leptothrix 
buccalis maxima of Miller are probably identical with the above. 



B B 




Fig. 377. — Bacillus buccalis maximus. Preparation similar to Fig. 462. 
Magnified 800 times, b.b. Bacillus buccalis maximus; B. Large rod-shaped form; 
N. Nucleus of partially-digested epithelial cell. 



Various types of the so-called spore-forming organisms of the soil 
are met with in stained preparations. These can be readily 
separated in cultures. Among them we find the Bacillus subtilis; 
Bacillus mesentericus fuscus, which is identical with the Bacillus 
gangrenes pulpcc of Arkovy; 2 Bacillus mesentericus ruber and others. 

Non-sporulating rod-shaped organisms of various types may be 
noted, as the Bacillus proteus vulgaris. Bacillus coli — organisms 



1 Archives de physiol., normal path., 1886. 

2 Vierteljakresshrift jiir Zahneilkunde, Jahrgang, xiv 



446 



THE ORAL FLORA 




Fig. 378. — Various forms of micro-organisms from the mouth' direct. The 
fine threads are Miller's Leplolhrix innominata: the thick chain is Bacillus -huccalis 
maximus. (From Goadby's "The Mycology of the Mouth.") 




Fig. 379. — Leplolhrix huccalis maxima, and Bacillus buccalis maximus. From 
approximal surface of a tooth. Magnified 1,500 times. (Photomicrograph by 
Leon Williams.) 



ORAL MICROBIOLOGY 



447 




Fig. 380.' — Spirillum sputugenum from mouth direct. Stained with gen- 
tian aniline violet. Magnified 1,000 times. (Trans. Odonto. Soc. of Great 

Britain.) 




Fig. 381. — Spirillum sputugenum (comma forms) from mouth direct. Stained 
and magnified as in preceding Fig. and from same source. 



448 



THE ORAL FLORA 



that cannot possibly be recognised except by isolating and studying 
their characteristics. 

Members of the Spirillum group are found in a large percentage 
of cases. The organism known as the Spirillum of Miller, Spirillum 
sputugenum, or Microspira Milleri, which occurs as short slender 
comma-shaped cells, is not infrequently encountered. The only way 
in which this organism can be differentiated from other Microspira 
is by isolation and culturing. 

The important Spirochatac or Treponemata have already been 
considered. 



V 



J 



r \ 




Fig. 382. — Spirillum sputugenum, freshly isolated from the mouth. Spiral 
forms not yet well developed. Magnified 1,000 times. (Trans. Odonto. Soc. of 
Great Britain.) 



Strikingly interesting organisms, probably more interesting than 
important, are certain of the C hlamydobacleriacece or sheath organ- 
isms. The Cladothrix dichotoma is occasionally observed, but 
cannot be distinguished from certain other thread-like organisms, 
in preparations made direct from the oral cavity. In cultures it is 
readily differentiated from all, excepting the Streptothrix buccalis, 
and from this by careful morphological study. It occurs in the form 
of long threads, straight or curved, apparently branched. It is of 
no pathological significance. The Lcptothrix innominata of Miller 
occurs in slender threads from 20 to 30/x in length usually straight, 
at times curved, rarely segmented, frequently presenting small gran- 



ORAL MICROBIOLOGY 449 

ules. This organism has never been isolated and identified as such. 
It presents a sheath when stained by appropriate methods, therefore 
it would appear to be a true Leptothrix. 

The so-called Leptothrix racemosa of Vicentini is very frequently 
discovered in the oral cavity, and has always attracted a great 
deal of attention on account of its striking form. Vicentini at one 
time looked upon this organism as the parent, as it were, of all bac- 
teria found in the sputum. This of course was many years ago 
when the theory of pleomorphism was receiving a great deal of un- 
deserved attention. The organism has never been isolated. Where 
it should actually be placed in the cryptogamic classification is not 
known; it is not a true Leptothrix. The writer has suggested on 
several occasions that it be classified for the present with the Fungi 
imperfecta. 

It has been studied in detail morphologically by Vicentini and 
Leon Williams. Owing to the fact that the organism is of con- 
siderable historical and biological interest, if probably non-important 
pathogenically, the description given in the first edition of this book, 
reading as follows, is appended. 

"Considerable interest has lately attached to the Leptothrix race- 
mosa, an organism first described by Filandro Vicentini in a series 
of contributions to the International Journal of Microscopy and 
Natural Science, 1894-1895, entitled the 'Bacteria of the Sputa and 
the Cryptogamic Flora of the Mouth.' By a special method of 
staining he discovered the organism in the materies alba, of 
Leuwenhoek. 1 Preparations were made before the first morning 
meal. This highly specialised form of Leptothrix is said to resemble 
the algae. It is a long, thread-like micro-organism having segmenta- 
tions or subdivisions, is uncoloured by iodine or weak acids, and at 
present is quite uncultivable. If the materies alba be examined, 
it will be found to contain, beside micrococci and bacilli, long, inter- 
lacing filaments, non-jointed, and non-coloured violet by iodine or 
acid. Vicentini wished to change the term Leptothrix buccalis to 
Leptothrix racemosa in order to represent its sporulation. This 
spore formation is only found in the superficial threads of the mass, 
the older filaments apparently being devoid of them. 

"The female element consists of a central thread or stem, peduncles 
arranged in six rows, sporules and a gelatinous envelope. In other 
words Leptothrix racemosa is a thread-like organism found in the 

1 Opera omnia sive arcana naiiiroe ope Microscopiorum exactissimorum detects. 
1722. 

29 



45° 



THE ORAL FLORA 




Fig. 3S3. — I.eplothrix racemosa. {Photomicrograph by Leon Williams.) 




Fig. 384. — Leplolhrix racemosa. (Photomicrograph by Leon Williams.) 



ORAL MICROBIOLOGY 



45 1 



microbial placques of the interdental spaces during the hours of 
fasting, and has beaded stems which bear at their extremities fructi- 
fying heads containing six or more rows of spores (Fig. 385). 

"Vicentini considered that the microorganism passes through four 
phases in its life history. First, that common to all bacteria, and 
undifferentiated from them; second, a stage of transition, in which 




Fig. 385. — Leptolhrix racemosa. "Fructification heads." From approximal 
surface of a tooth. (Photomicrograph by Leon Williams.) 

there may be recognised 'chains, bundles, and masses of inter- 
twined filaments, isolated filaments, large dumb-bell bacteria, and 
masses of diplococci, the large dumb-bell bacteria being derived 
from the diplococci, the true original cocci linking together.' The 
third phase occurs with the deposition of tartar on the teeth. Here 
he described large threads, often massed together in bent, filamentous 



452 THE ORAL FLORA 

forms, which presented the peculiar appearances of branched or 
barbed radial extremities and bulbous terminations. And in the 
last phase, which Vicentini called that of 'fructification' or 'com- 
plete aerial vegetation,' the fertile heads or extremities assume a 
more complicated appearance, and exhibit the formation of spores 
arranged in three longitudinal rows. 'The fertile filaments are 
sometimes straight, at others bent or curved, occasionally they are 
entirely wanting, because the fructifications have been carried away 
by mechanical force.' 'Gemmules of reserve' adhere to the pe- 
riphery of the stem. 

"Vicentini believes that in its method of reproduction this organism 
follows two methods — the endogenous spore formation, and the con- 
jugated fructification or acrogenous abjunction, in which spores are 
found at the apices of the cryptogam. The terminal cell becomes 
enlarged and converted into a tiny base called the basidium, from 
which arise minute stalks or sterigmata, carrying spores upon their 
terminal ends. 

"In this way it is possible that Leptothrix racemosa possesses 
veritable organs of reproduction and therefore resembles fungi 
and the diascious algae. The male elements have a morphological 
likeness to blossoms formed of spindle or fern-shaped points. 

"Vicentini believed that this micro-organism is the parent of all 
but one of the varieties found in the sputum. Thus he asserts that 
Bacillus buccalis maximiis and Leptothrix biiccalis represent merely 
its broken stems and filaments, Iodococcus vaginatus the 'gemmules 
of reserve,' and the Spirillum s piitugenum , the appendages or 
branches of the male elements. 

"Much of this work is corroborated by Leon Williams, who, how- 
ever, does not hold entirely with all his views." 

THE MICRO-ORGANISMS OF DENTAL CARIES 

The organisms found in dental caries are of various types; some 
active in the various stages of the process, others simply present as 
accidental invaders and of no significance as far as the condition is 
concerned. 

Miller demonstrated conclusively that dental caries was caused 
essentially by bacterial action, isolating bacteria from carious teeth 
and furthermore producing all stages of caries artificially. 

Goadby grouped the organisms of dental caries into three classes: 
namely those having the property of (A) forming acid, (B) of 
peptonising dentine; and (C) producing pigmentation. He also 



ORAL MICROBIOLOGY 453 

mentions a number of organisms found in a group of cases 
studied. Our experience has been that the organisms encountered 
in the mouth and in the various stages of dental caries vary to a 
great extent and that by special methods of cultivation, some are 
noticed which ordinarily are not found. Therefore it seems out 
of place in this chapter to attempt to name all of the different 
organisms concerned in the process. 

The organisms concerned in the various stages may be grouped 
as follows: 

I. Those entering into plaque formation. Various types of cocci, 
bacilli, leptothrix and streptothriciae. These have been 
considered in sufficient detail under the findings in stained 
preparations. 

II. Those concerned in acid formation. To attempt to name and 
consider all organisms associated with dental caries would be 
inexcusable in this chapter; the following statement covers the 
entire situation. Any organism capable of developing in the 
oral cavity, and of forming acids by splitting carbohydrates, 
may play a part in dental caries by forming organic acids, the 
most important of which are acetic and lactic, which by their 
constant or intermittent action, notably on protected surfaces, 
underneath plaques, etc., disintegrate enamel. Butyric and 
succinic acids are also formed, and they are claimed by some to 
exert a similar action. 

Some speak of acid-producing organisms in this connection and 
actually believe that the organisms produce acids. The facts 
are as follow: The micro-organisms produce enzymes of 
various kinds, some of which have the property of splitting up 
carbohydrates into simpler compounds, amongst which are the 
acids already named. 

III. Those disintegrating dentine: 

(A) Acid formers as above, the acid dissolving the lime salts 
in the dentine. 

(B) Various organisms capable of digesting proteins. This 
might include any organism capable of developing in the 
oral cavity producing proteolytic enzymes or decarb- 
oxylases and deamidases. The above groups may be 
divided as follows: 

(a) Those acting on the superficial layers of carious dentine. 
(1) Aerobic: those acting (developing) only in the 
presence of free oxygen. 



454 THE ORAL FLORA 

(2) Aerobic facultative: those acting both under 
aerobic and anaerobic conditions (Fig. 146). 
(b) Those acting on the deeper layers of carious dentine. 

(1) Aerobic facultative. 

(2) Anaerobic: Those not capable of developing in the 
presence of free oxygen, but growing only under 
strict anaerobic conditions. The conditions in 
deeper caries, underneath masses of food-debris- 
filled cavities, and underneath temporary and 
permanent fillings, are ideal for their development. 




FlG. 386. — Bacillus necrodenlalis. Showing pleomorphism. Forty-eight 
hours' cultivation of agar. Stained by Gram's method. (Magnified 1.000 
times. (Trans. Odonto. Soc. of Great Britain.) 



Bacterial proteolytic enzymes are of two types: (1) Of the nature 
of pepsin, carrying the cleavage of protein as far as the formation 
of peptone; (2) Of the nature of trypsin carrying the cleavage of 
protein so far as the formation of amino acids. 

The so-called putrefactive changes in caries, made manifest by 
the presence of a decided aromatic odor, are due to the end-products 
formed by the deamination and decarboxylisation of the amino 
acids, chiefly some of the higher open chain acids and those of the 
benzene series. This action is exerted by various types of bacteria 
under anaerobic conditions. 

The organisms in the deeper layers of carious dentine have been 
the subject of some investigation and much discussion. The pre- 



ORAL MICROBIOLOGY 455 

vailing opinion is that they are not numerous. Goadby gives as 
quite constantly present an organism which he isolated and called 
the Bacillus necrodentalis, the Streptococcus brevis, and Staphylo- 
coccus albus. The first is an anaerobe, the other two facultative. 
Organisms of the so-called Moro-Tissier 1,2 group of intestinal bacteria 
have been found in the deeper layers of carious dentine by Kleigler, 3 
Howe 4 and others. Their relationship to the process is apparently 
an important one. 

1 Jahresberichte fur Kinderheilkunde, 1900 and 1905. 

2 Annates dc Vlnstiiul Pasteur, 1900. 

3 Journal of Allied Denial Societies, 1915. 

4 Journal of Medical Research, 1917. 



PART III 
THE EXTRA-ORAL DENTAL TISSUES 



CHAPTER XVII 

"DERMOID" TEETH, OR TEETH DEVELOPED IN 
TERATOMATA 

Relation of teeth to Teratomata — Varieties — Eruption — Development- 
Shedding — Anatomy and Histo-pathology — Bony attachments — 
Relation of "Dermoid" teeth to Hair — "Dermoid" teeth in the 
testis — Conclusions. 

"Dermoid" teeth, or teeth developed in teratomata, are of in- 
terest to the embryologist, the pathologist, the surgeon, and, to 
the dentist. Teeth appearing elsewhere than in the maxilla or the 
mandible must be considered as abnormal. The origin of such 
is now believed to be almost certainly connected in every case with 
a teratoma. These teratomata occur most commonly in the ovary, 
in the neck, and possibly in the testis. They are seen in the human 
subject, and also in animals of a lower grade. When occurring in 
the neck, a teratoma is probably an anterior dichotomy, abortive 
in most cases. These remarks are confined to the dental structures 
which are by no means infrequently discovered in those cysts not 
uncommonly associated with the human ovary, and have been for 
long termed "dermoid cysts." 

In i860, Salter 1 published an excellent account of these teeth, 
while in 1863 Alfred Coleman 2 presented another. In 1890 
T. Charters White and J. Bland-Sutton 3 jointly read a most in- 
structive contribution to the subject, and later S. G. Shattock 4 
summarised in a brilliant article, the then-existing knowledge of the 
subject. 

"dermal" tissues 

An ovarian "dermoid" is a true teratoma. 

It is interesting to note that it is what may be called the "dermal" 
tissues which seem to be most in evidence. There is abundance of 
skin, often much hair, and this of two kinds, fine lanugo- 

1 Guy's Hosp. Reports, i860. 

- Trans. Odont. Soc. of Great Britain (1863-65), 1865. 

3 Dental Record, 1890. 

4 Trans. Path. Soc, 1907. 

459 



460 



THE EXTRA-ORAL TISSUES 



like, and long and scalp-like, each growing from its own appropriate 
part of the foetus, and teeth, sometimes only one, often many, and 
occasionally exceedingly numerous. Also in a few instances nails 
or horny structures have been observed. 

RELATION OF TEETH TO TERATOMATA 

The exact position of these teeth in relation to the teratomatous 
tissue and to the actual cyst wall is a matter of some interest and 





v«4fe 


. 










. "pt * 


M fl - 


T 
T T 


HW'-wjIf jd 


' r 


T T T 




w 






- 



c w 



c c 



Fig. 387. — An ovarian teratomatous cyst laid open to show contents. C.W. 
Cyst wall; c.c. Cyst cavity; t. Caniniform tooth; t.t. Another portion of the 
teratoma, possibly an arm; t.t.t. Possibly the scalp. 

importance. The teeth may be found (1) embedded in bone in 
actual alveoli or sockets, (2) embedded in soft tissue, either of the 
foetus or possibly of the cyst wall, or (3) free within the cyst cavity. 
There is no reason why a teratomatous foetus should not possess 
an ill-formed maxilla or mandible, and no reason why such a jaw 



TEETH DEVELOPED IN TERATOMATA 



461 



should not carry teeth. Hence the appearance on, or in the tissue 
forming the foetus, of bone with attached teeth is easy of explana- 
tion; but it is difficult to account for those instances where teeth 
have been found at some distance apparently from the actual site 
of the fcetal tissues, and attached to soft tissues only. There are 
three possible explanations: First, that during the development of 
the cyst, associated with which is the foetus, pressure has caused a 
lateral displacement of a part of the foetus, so that the tooth-bearing 
area has, as it were, become flattened out, leading to an elongation 



T T 




TTT 



C W 



Fig. 388. — A portion of an ovarian teratomatous cyst laid open to show con- 
tents, c.w. Cyst wall; b. Bone to which teeth were attached; t. Caniniform 
tooth; t.t. Premolariform tooth; t.t.t. Molariform tooth. 



of the tooth band. Secondly, there may have been a homologous 
twin which has developed very much less than its fellow, in fact, 
the teeth may be the sole evidence of its existence. It is possible for 
the same ovary to contain three separate teratomata, or triplets, and 
thus for the number of teeth present to be considerable, and their posi- 
tion remote in relation to the obvious teratoma. Or, thirdly, it may 
be an anterior dichotomy of the teratoma, thus allowing for at least a 
second dentition. 

It is always the cephalic end of the .teratoma in which these "der- 



462 THE EXTRA-ORAL TISSUES 

moid" teeth arise, and, in fact, the dental structures may in some 
instances be the only evidence of the cephalic end of a trunkless 
(acormous) teratoma. 

VARIETIES 

The morphological variations in teeth associated with ovarian 
teratomata approximate very closely to those usually found in the 
human mouth. Incisors, canines, premolars and molars have their 
counterparts in these cysts. The premolariform and caniniform 
types predominate from the point of view of number. The teeth 
themselves are generally well developed, and bear few, if any, traces 
of any degeneration of their exposed portions. Seldom, if ever, 
have purely conical representatives been noticed in these cysts. 
Sometimes, however, very numerous malformed dental bodies are 
met with. These possess but little resemblance to ordinary human 
teeth. 

The cause of such enormous quantities of these denticles is 
difficult to determine. It may be that an extended tooth band has 
given rise to myriads of aborted, but more or less calcified, tooth 
germs. Or that fenestration and total disappearance of the inter- 
vening portions of the tooth band have occurred in the usual way, 
and that arrest of complete development, caused by the abnormal 
environment to which they have been subjected, coupled, perhaps, 
with the precocity and rapidity of their growth, has resulted in the 
display of congeries of misshapen, irregular masses composed mainly 
of enamel and dentine. Although these teratomatous cysts are 
tooth-bearing cysts, they are in no sense dentigerous cysts, and it 
would appear to be extremely likely that the same operations of 
pathogenesis may be acting here as in similar fashion to those which 
act sometimes in the jaws. It is not beyond the bounds of possi- 
bility that there may be occasionally a multiplicity of tooth-bearing 
cysts, which ultimately are capable of becoming incorporated in 
one large cavity. 

DEVELOPMENT 

In "dermoid" oophoronic cysts "epithelial pearls" exist. The 
cells are large, become compressed as they approach the peripheral 
portion of the "pearl," and are finally lost in the surrounding cap- 
sule. They are ingrowths from the surface epithelium, which be- 
come isolated in the mesodermic tissue, and are allied to enamel 
organs, being attached to the free surface where they arose. Many 



TEETH DEVELOPED IN TERATOMATA 



46/5 



ovarian tooth germs lack a definite fibrous capsule. (See Fig. 256, 
Vol. I.) 

The so-called "pearls" may remain cellular, or give rise to the 
formation of enamel, or undergo transformation into horns or nails. 

ERUPTION OR NON-ERUPTION OF TEETH 

Of the actual dynamics of the eruption of ovarian teeth it is impos- 
sible to speak. Many of the oral conditions which assist this phe- 
nomenon are entirely absent. The growth of bone when present may 
have some bearing upon the eruption, but this cannot hold in those 




Fig. 389. — Part of the contents of an ovarian "dermoid" cyst. T. Three 
well-formed premolariform teeth; h. A bundle of hair; a. A mass of teratomatous 
bone. (Photograph by Mr. Dencer Whittles.) 



instances in which teeth are erupted from the wall of the "dermoid" 
in places where no bone exists. 

Many cysts contain enamel organs which have not proceeded to 
maturity. It would seem that many teeth while fully developed, 
except perhaps as far as their roots are concerned, do not become 
extruded through the superficial soft parts, though evidences are 
not wanting that generally, by virtue of their rapid and precocious 
growth, they do completely erupt on the surface of the teratoma. 

There is no evidence of any eruption of a second dentition such 
as occurs in the normal mouth. 



464 



THE EXTRA-ORAL TISSUES 



SHEDDING 

In the ovarian embryomata hair is frequently shed. The same 
cause may be at work in producing this separation as in the case of 
other epidermal derivatives. The implantation of the ovarian 
teeth is comparatively feeble in character. They are retained in 
the fresh condition by a thin annular elevation of connective tissue 
at their necks, and in many dried specimens there is an appearance 
as if the marginal bone had become absorbed, or, at all events, 
had never been fully developed. The necks of the teeth are well 




Fig. 390. 



-Vertical section of the enamel. Magnified 55 times. 
D. Dentine. A. Amelo-dentinal junction. 



E. Enamel. 



exposed and vary in depth, and often their roots are visible above 
the free surface of the bony alveolus. 

It is possible that when a tooth is found free within the cavity of 
the cyst, it has been shed by senile changes, in an acardiac, acor- 
mous parasite as part of a pathological retrogression which is en- 
tirely different from, and antecedent to, that of the host. But in 
other cases it may but be an accidental detachment during the re- 
moval of the cyst from the body. 



ANATOMY AND HISTO-PATHOLOGY 



For the most part the teeth found in ovarian teratomata exhibit 
the main characteristics of those of the human permanent denti- 



TEETH DEVELOPED IN TERATOMATA 



46S 



tion, though on the whole they are smaller. In those examined 
they measured about 5.5 mm. in their extero-internal diameter 
(which would correspond to the bucco-lingual direction in the mouth) 
and 17 mm. in extreme length. But, of course, many variations 
of mensuration are met with. In those specimens specially exam- 
ined for the purpose, the translucent pellicle of Nasmyth's mem- 
brane was found. 



-1 




D Z 



Fig. 391. — Vertical section of an ovarian tooth. Decalcified. Stained with 
hasmatoxylene. Magnified 45 times, d. Dentine; p. Pulp tissue; ©.Odonto- 
blasts; D.z. Dentogenetic zone. 



A root is generally present, being joined to the crown sometimes 
without the usual cervical constriction. Seldom is a tooth bi-rooted, 
and a multi-rooted tooth is very rare. The roots taper to a point. 

On section a pulp cavity with root canal can usually be observed. 
In extremely thin incisiform specimens this is often narrowed down to 
an inconspicuous canal, and even this at times may be wanting. 
In the fresh condition pulp tissue is present, and bundles of myelinic 
nerve fibres can be seen accompanying the blood-vessels. When no 
3° 



466 



THE EXTRA-ORAL TISSUES 




D Z 



Pig. 392. — Section of an ovarian tooth with pulp in situ. Stained with 
haematoxylene. Magnified 200 times, d. Dentine, d.z. Dent ogenetic zone; p. 
Pulp; o. Odontoblasts. 



v • 





Fig. 393. — Similar to preceding figure, d. Dentine; o. Odontoblasts; n. Mye- 
linic nerve fibres. 



TEETH DEVELOPED IN TERATOMATA 



467 



actual cavity exists, dentinal tubules radiate more or less from a 
common centre outwards, but in some sections, the tubules run 
centripetally as well as centrifugally (Fig. 65). 

Enamel, dentine and cementum are present. The first is fairly 
normal, the second of an incompletely developed character, as 
proved by the abundance of interglobular spaces. Cementum is 
frequently absent. If it is present, it constitutes a very thin external 
band of the dentine, just beyond the homogeneous layer and the 
granular layer of Tomes. The pathology of these teeth has been 
cursorily described by Wedl (Atlas der Path, der Zahne, 1903). He 
believes that erosion of the superficial parts may take place. He 




Fig. 394. — Similar to preceding, d. Dentine; p. Pulp; o. Odontoblasts; n. 

Myelinic nerve fibres. 



has not seen dental caries, which is to be expected, inasmuch as the 
contents of the embryomatous cyst are generally of a thick alkaline 
nature, and suppuration often occurs. Mr. Shattock says that 
enamel nodules may sometimes be seen upon the roots. The 
teeth are clumped together, and are malplaced when found embedded 
in the teratomatous bone. Instead of occupying a definite relation- 
ship to each other, as in the mouth, they are placed irregularly 
with regard to one another, possibly from the fact that here there are 
no mechanical factors such as are produced by the action of the soft 
tissues of the tongue and cheek or lips in giving rise to the proper 
alignment of the teeth in the dental arch. 



468 THE EXTRA-ORAL TISSUES 

BONY ATTACHMENTS 

Some of the pieces of bone in which these ovarian teeth have been 
found are exceedingly like small maxillas or ill-developed mandibles. 
One peculiarity, however, is often present, namely, that whereas the 
size of the "jaw" itself is much less than the size of the jaw of the 
host, the teeth themselves found in the ovary may be almost, if not 
quite, as large as those found in the normal mandible of the host. 
The bone itself is of poor quality, and consists mainly of cancellous 
tissue. 

RELATION OF "DERMOID" TEETH TO HAIR 

As a rule the teeth in the teratomata of the ovary bear no relation- 
ship to the hair growing from the same parasite, other than that 
they will be found in their own normal position in reference to the 
cephalic end of the teratoma, and the long hairs will be springing 
from the scalp portion of the foetus, also at the cephalic end. But 
sometimes short, rather stubbly hairs are found growing, in a ringlet, 
actually round the neck of the tooth from the soft tissue which might 
be said to be forming the gum. This fact is interesting as showing 
the close possible connection between the two dermal structures, 
hairs and teeth. 

X-RAY EXAMINATION OF "DERMOID" TEETH 

The X-ray examination of "dermoid" teeth is interesting from 
several points of view. The teeth, like normal teeth, obstruct the 
passage of the rays more markedly than does the bone by which 
their roots may be surrounded. Hence it is quite possible that an 
X-ray examination of a living subject who is the host of a dermoid 
cyst of the ovary might reveal the presence of the cyst by the marked 
shadow thrown by the teeth, if any were present, in contrast to 
the shadow thrown by the pelvic bones. 

A radiograph will also indicate the presence of a pulp cavity in the 
interior of the "dermoid" teeth. It will also show the character 
of the bone associated with the teeth, if any bone exists. 

"dermoid" teeth in the testis 

There are on record several cases of a dermoid cyst of the testis 
in the human subject, but the condition must be considered as an 



TEETH DEVELOPED IN TERATOMATA 469 

extremely rare one. A similar cystic enlargement of the testis of the 
horse is not so uncommon, and particularly where the testis is 
retained. One case at least, occurring in the human subject, pre- 
sented a tooth borne by a teratoma in the testis. In the case of the 
horse there have been found similar teeth. 

While the origin of ovarian " dermoids" may now be considered as 
settled, it is difficult to conceive that the testis can be the host of a 
teratoma with an identical origin. Prof. Shattock has put forward 
the suggestion that these "dermoids" of the testis are in reality 
teratomata of the ovary portion of an ovi-testis gland in a true 
hermaphrodite. This is certainly quite feasible, and some amount 
of confirmation is obtained from the presence of a teratoma asso- 
ciated with an imperfectly descended testis in a "rig" horse. Such 
an animal is not infrequently vicious and unsuitable for domestic 
purposes. The removal of the retained testis has the effect in 
many instances of rendering the animal docile and useful. 

CONCLUSIONS 

The presence of teeth in dermoid cysts of the ovary, and of the 
testis, tends to prove the teratomatous nature of these tumours. 

The similarity between dermoid cyst teeth and those of the normal 
human mouth tends further to indicate their teratomatous origin. 

The period of eruption of the "dermoid" teeth does not coincide 
with the period of eruption of the teeth of the host, but is probably 
earlier, and their growth is more rapid. It is possible that this 
precocity may be due to the influence of the super-host through her 
blood. 

There is no distinct evidence of the shedding of "dermoid" 
teeth, and there is no evidence of any distinction between a deciduous 
and a permanent dentition. 

While "dermoid" teeth may be ill-shapen and may otherwise 
deviate from the form of normal teeth, there is no evidence of any 
pathological process which can be termed "caries." 



INDEX TO VOL. II 



Abrasion of enamel, 22 

Abscess of periodontal membrane, 255 

Of pulp, 1 59 
Absorption of dentine, 55 

Of enamel, 23 

Pathological, 25, 55, 59, 282 
Ackery and Colyer on absorption of 

dentine, 68 
Actinomycosis, 437 
Acts, obscure reflex, 223 
Acute caries, no 

Adenoma, 330, 343, 352, 353, 400, 401 
Adventitious bacteria of mouth, 443 
Adventitious dentine, 71, 157, 164, 
210, 215 

Areolar, 72 

Cellular, 72 

Fibrillar, 73 

Hyaline, 74 

Laminar, 76 
Alexins, 153 
Alveolo-dental periosteum, abscess of, 

255 

Carcinoma of, 268 

Cyst of, 258 

Degeneration of, 306 

Fibroma of, 225 

Inflammation of, 254 

Morbid Affections of, 254 

Sarcoma of, 265 

Tumours of, 264 
Angina Ludovici, 427 
Angioma, 328, 342 
Ankylosis of teeth, 80 
Anthrax, 433 
Antrum of Highmore, adenoma of, 

352, 353 

Carcinoma of, 349 

Inflammation of, 349 

Sarcoma of, 329, 352 
Aphthous stomatitis, 354 
Areolar adventitious dentine, 72 



"Arrested caries," 138, 213 
Ascomycetes, 413, 420 
Atrophy of pulp, 195 
Attrition of enamel, 29 

Bacillus aerogcnes capsnlatus, 420, 434 
Bacillus anthracis, 420, 433 

Buccalis maximus, 445 

Colt, 445 

Diphtheria, 420, 431 

Fluorescens liquefaciens motilis, 
140 

Furvus, 140 

Fusiformis, 420, 438 

Gangrencc pulpa, 445 

Influenza, 420 

Mallei, 420, 433 

Mesentericus juscus, 445 

Mesenlericus ruber, 445 

Mucosus capsnlatus, 420, 433 

Necrodenlalis, 140, 209, 455 

Plexiformis, 140 

Proteus vulgaris, 445 

Pseudo-diphthcriticum, 420 

Subtilis, 140, 445 

Tetani, 420, 434 

Tuberculosis, 420, 422, 432 
Bacteria, 411 
Bacterium, 414 

Baker, A. W. W., on absorption of 
dentine, 57, 58 

On dental cysts, 262 
Basidiomyceles, 413 
Baume on erosion of enamel, 31 

On translucent zone of caries, 120 
Beggialoacca, 415 

Bennet on absorption of dentine, 66, 
67, 68 

On translucent zone of caries, 118 
Black on absorption of dentine, 58 

On atrophy of pulp, 190 

On calcification of pulp, 179 



47i 



472 



INDEX 



Black on changes in dentine, 208, 209 
Bland-Sutton on absorption of teeth, 
58 
On odontomes, 371, 381 
Blastomyces dermatitis, 440 
Blaslomycetes, 39, 440 
Bone, osteoporous atrophy of, 283 
Bretland Farmer, Moore and Walker on 

cancer, 367 
Bryophyta, 413 

Buckley on putrefaction of pulp, 169 
" Burrowing epithelioma" of jaws, 268 

Calcareous degenerations of pulp, 

196, 231 
Calcott Fox and McLeod on Paget's 

disease, 368 
Cancrum oris, 354, 439 
Capsule of odontomes, 394 
Carcinoma of antrum, 349 

Columnar, 344 

Diagnosis of, 328 

Of jaws, 344 

Of periodontal membrane, 268 

Spheroidal-celled, 344 

Squamous-celled, 344 
Caries acuta, 101 
Caries "arrested," 138, 213 

Chronic, 74, 101 

Chronica, 101 

Humid a, 10 1 

Sicca, 101 
Caush on absorption of dentine, 65, 66 
Cell-nests, 346, 347, 360 
Cellular adventitious dentine, 72 
Cemental nodules, 80, 372, 385 
Cementomes, 372, 385 
Cementum, ankylosis of, 80 

Hyperplasia of, 86 

Pathological conditions of, 80 

Senile, 100 
Charbon, 435 
Chemiotaxis, 153 
Chlamydobacteriacem, 415 
Cladothrix, 415 

Cladothrix dicholoma, 438, 448 
Classification of Bacteria and Proto- 
zoa, 413, 415 

Of plants, 412 



Coccacea, 413 

"Coccidia," 360 

Composite odontomes, 371, 372, 391 

Congenital pigmentation of dentine, 53 

Crenothrix, 415 

Cryptogams, 411, 412 

Cuneiform defects in enamel, 30 

Cyst, dental, 258 

Dentigerous, 372 

Differential diagnosis of, 401 

Eruption, 381, 401 

Of teeth (odontocele), 399 

Degenerations of the oral mucous 
membrane, 354 

Calcareous, 196, 231 

Fatty, 196 

Fibroid, 187 

Malignant, 356 

Of the periodontal membrane. 306 

Of the pulp, atrophic, 195 
Dental caries (see Caries). 
Dental cyst, 258, 329, 330, 352, 372, 400 

Baker, A. W. W. on, 260, 262 

Turner on, 260, 262 
Dental pulp, atrophy of, 195 

Calcification of, 177, 180, 196 

Carious lesions of, 207 

Degenerations of, 187 

Diseases of, 143 

Dyaesthesia of, 226 

Gangrene of, 168 

Healing processes in, 182, 183 

Hyperemia of, 144 

Hyperesthesia of, 226 

Hyperplasia of, 165 

Inflammation of, 151, 164 

Injuries of, 174 

Nodules of, 198, 202 

Non-carious lesions of, 219 

Pathology of, 143, 206 

Physiological resistance of, 210 

Putrefaction of, 169 

Receptivity of, 226 

Vascular lesions of, 232 
Dentigerous cyst, 372 
Dentine, absorption of, 55 

Adventitious, 71, 157, 164, 210, 
215 



INDEX 



473 



Dentine, bone in, 68, 69 

Caries of, 115, 130, 132, 135, 142 

Congenital pigmentation of, 53 

Defects of, 51 

Dilaceration of, 42 

Gemination of, 43 

Nanoid, 54 

Pathological pigmentation of, 76 

Senile, 76 

Syphilitic, 21 

Vascular canals in, 55 

"Of repair," 34, 205 
Dentz on defects in dentine, 51 
"Dermoid" teeth, 459 
Diagnosis of cysts of jaws, 401 

Of fluid swellings of jaws, 329 

Of inflammation of pulp, 255 

Of sarcoma and carcinoma, 328 

Of stomatitis, 354 

Of swelling of mandible, 331 

Of swellings of palate, 330 

Of tumours, 327 
Differential diagnosis of cysts of 
jaws, 401 

Of pulpitis and periodontitis, 255 

Of stomatitis, 354 

Of swellings of jaws, 329 
Dilaceration, 42 
Diphyodontic gemination, 50 
Diplococcns pneumonia, 139, 420 
Disturbances of sensation, 236 
Dolamore on composite odontome, 391 
Duckworth on fungoid excavation of 
enamel, 39 

Enamel, abrasion of, 22 
Absorption of, 23 
Attrition of, 29 
Caries of, 107, 141 
Channelling of, 37 
Erosion of, 30 
Excavation of, 34 
Hypoplasia of, 4 
Nanoid, 16 
Nodules, 9, 372 
Pigmentation of, 14 
Rachitic, 18 
Syphilitic, 19 
Zsigmondy on hypoplasia of, 5 



Enchondroma, 331 
Endamosba, 415, 418 
Endamceba gingivalis, 418, 442 
Endospores, 411 
Endosteal fibroma, 333 
Endothelioma of jaws, 340 
Epithelial odontomes, 372 
Epithelioma, 344 

"Burrowing," 268 
Erosion of enamel, 30 

Theories of, 31 

Znamensky on, 31 
Eruption cysts, 381, 400, 401 
Eubacteriaceee, 413 
Euthallophyta, 413 
Exostosis of jaws, 349 
Extensive absorption of dentine, 59 
External absorption of dentine, 57 

Of enamel, 23 
Extra-capsular odontocele, 404 

False gemination, 43, 44, 46, 47 
Fatty degeneration of pulp, 196 
Fibrillar adventitious dentine, 73 
Fibroid degeneration of periodontal 
membrane, 306 

Of pulp, 187 
Fibroma, endosteal, 333, 385 

Of jaws, 330, 331, 357, 359 

Of periodontal membrane, 265 

Periosteal, 333 
Follicular odontome, 376, 385 

Bland-Sutton on, 377, 381 

Heath on, 382 

Paul on, 382 

Tomes and Nowell on, 381 
Fracture of teeth, 183 

Storer-Bennett on, 185 
Fungi imperfecta, 412, 413 
Fungoid excavation of enamel, 34 

Gangrene of pulp, 168 

Schenk on, 171, 172, 173 
Gassmann on chemical differences in 

dental tissues, 218 
Gemination of teeth, 43 

Diphyodontic, 50 

False, 43, 44, 46, 47 

True, 43, 46, 49 



474 



INDEX 



Gingivitis, 322 

Goadby on Bacillus necrodcntalis, 209, 

455 
Gonococcus, 420, 424 
Granulation tissue, 294 
Gum, diseases of, 322 

Endothelioma of, 340 

Epithelioma of, 343 

Fibroma of, 331 

Hypertrophy of, 324 

Inflammation of, 322 

Papilloma of, 340 

Sarcoma of, 334 

Syphilis of, 348 
Gumaisthenic perceptions, 224 
Gumma of palate, 348, 349 

Halisteresis, 57, 282, 283 
Hemangioma of palate, 342 
Hemolytic streptococci, 425 
Head on disturbances of sensation, 235 
Healing processes in dental pulp, 174 
Hektoen and Riesman on Cell 
Nests," 347 
On Inflammation, 152 
On Osteitis rarefaciens, 285 
"Hutchinsonian teeth," 20 
Hyaline adventitious dentine, 74 
Hydropic degeneration of epithelium, 

330- 360 
Hyperemia of pulp, 144 

Bodecker on, 148 

Etiology of, 145 

Regional, 212 
Hyperostosis of jaws, 351, 352 
Hyperplasia of cementum, 86 

Of dental pulp, 165 
Hypertrophy of gum, 324 

Roe on, 327 
Hyphomycetes (Moulds), 410, 412 
Hypoplasia of enamel, 4 

Impacted fractures of teeth, 183 
Inflammation, histology of, 151 
Inflammation of antrum, 349 

Of periodontal membrane, 254 

Of pulp, 151 
Injuries of pulp, 174 
Internal absorption of dentine, 64 



Internal absorption of enamel, 26 

Woods on, 26 
"Interruption lines" in enamel hypo- 
plasia, 7 
Iodococcus vaginatus, 444 

Jaws, carcinoma of, 344 

Exostosis of, 349 

Fibroma of, 330, 331, 357, 359 

Hyperostosis of, 351, 352 

Sarcoma of, 352 
Jeserich on "translucent zone" of 
caries, 119 

Keratin, 357, 358 

Karyoclasis, 366 

Karyolysis, 360 

Kirk on "bacterial plaques," 108 

Kolliker on lacunae in cementum, 89 

Lacunae, arborescent, 92 

Cemental, 89 

Encapsuled, 92 

Kolliker on, 89 

Plumiliform, 90 

Rimous, 92 
Lacunar absorption, 57 
Laminar adventitious dentine, 76 
Leber and Rottenstein on "translucent 

zone" of caries, 118 
Leon Williams on caries of enamel, 107, 
no 

On syphilitic enamel, 21 
Lepkovvski on vascular supply of 

dental tissues, 233 
Leplothrix, 415 
Leptothrix buccalis maxima, 132 

Innominata, 448 

Racemosa, 449 
Lesions of dental pulp, carious, 207 

Chemical origin of, 221 

Electrical origin of, 221 

Non-carious, 219 

Tactile origin of, 219 

Thermal origin of, 220 
Leuwenhoek's materies alba, 449 
Lingua nigra, 441 
Lipogenesis, 277 
"Liquefaction foci," 130, 135 



INDEX 



475 



Loos on senile changes in dentine and 

pulp, 213 
Ludwig's angina, 427 

Malignant degeneration of oral epi- 
thelium, 356 
Malignant pustule, 433 
Mast cells, 326 

Melanotic sarcoma of palate, 339 
Matcrics alba, 449 
Meningococcus, 420, 424 
Micrococcus, 413 
Micrococcus albus, 419, 421 

Aureus, 419, 421, 422, 423 

Catarrhalis, 420, 423 

Citreus, 419, 421 

Tctragenus, 420, 444 
Micro-organisms of dental caries, 139, 

435 
Micros pira, 414 

Miller on opaque zones of caries, 128 
On "pipe-stem" appearance of 

caries, 135 
On "translucent zone" of caries, 
117, 119 
Moulds, 410, 412 
Mucous membrane, degeneration of, 

356 
Mycobacteriacew, 414 
Mycobacterium, 414, 432 
Myxothallophyta, 412 

Nanoid dentine, 54 

enamel, 16 
Nasmyth's membrane, pathological 

affections of, 102 
Nodules of cementum, 80 

Of enamel, 9 

Of pulp, 198, 202 
Non-carious lesions of hard tissues, 219 

Obscure reflex acts, 223 
Odontalgig. 223, 226, 231, 235 
Odontoceles, extracapsular, 399, 400, 
404 

Subcapsular, 399, 400 
Odon tomes, 371 

Bland-Sutton on, 371, 381 

Capsule of, 394 



Odontomes, composite, 371, 372, 391 

Epithelial, 330, 352, 371, 372, 400, 
401 

Follicular, 330, 352, 371, 376, 377, 
385, 386 

Radicular, 371, 386 
Oidium albicans, 354, 421, 439 
Oomycetes, 413 
Opaque zone in caries, 128 
Ophthalmia neonatorum, 425 
Oral microbiology, 409 
Osteitis rarefaciens, 285, 303 
Osteoma of jaws, 330, 331, 343 
Osteoporous atrophy of bone, 283 

Nikiforoff on, 277 
Ousaisthenic perceptions, 225 
Ovarian teeth, attachments of, 468 

Development of, 462 

Dentine of, 467 

Erosion of, 467 

Eruption of, 463 

Nasmyth's membrane of, 465 

Of testis, 468 

Shedding of, 464 

Varieties of, 462 

Pain referred, 223 
Palate, carcinoma of, 330 

Cavernous angioma of, 342 

Hemangioma of, 342 

Melanotic sarcoma of, 339 

Papilloma of, 340 
Papilloma of gum, 330, 340 

Of palate, 340 
Pathogenic micro-organisms, 419 
Pathology of pulp, 206 
Periodontal membrane (see Alveolo- 

dental periosteum). 
Periosteal fibroma, ^^^ 
Phagocytosis, 153 
Phragmidiothrix, 415 
Phycomycetes, 413 
Pickerill on dental caries, 106 

On dentine, 53, 76 
Pigmentation of enamel, 7, 14 
"Pipe-stem" appearance in caries, 134 
Planococcus, 413 
Planosarcina, 414 
Pneumococcus, 420, 425, 430, 431 



476 



INDEX 



Pont on "sclerosed conditions" of 

pulp, 1 68 
Proteus vulgaris, 140 
Protozoa, 415 
Pscudomonas, 414 
Ptcridophyta, 413 
Pyogenic cocci, 421 
"Pyorrhoea alveolaris," 271, 422, 431, 
442 
Znamensky on, 272, 303 

Rachitic enamel, 18 
Ray fungus, 435 
Referred pain, 223 
Reflex acts, obscure, 223 
Rhizopus nigrans, 421 
Rhodobactcriacea, 415 
Russell's fuchsine bodies, 261 

Saccharomyces, 37, 40, 439 

Albicans, 439 

Nigrans, 441 
Sarcina, 140, 413, 4r4 
Sarcodina, 421 

Sarcoma of periodontal membrane, 
264, 265 

Diagnosis of, 328 

Melanotic, 339 

Myeloid, 337 

Round-celled, 336 

Spindle-celled, 334 
Schenk on gangrene of pulp, 171 
Schizomycetcs, 411, 413 
Schizophycea, 413 
Schizophyta, 411 
"Secondary enamel decay," 114, 115, 

141 
Senile cementum, 100 

Dentine, 76 

Pulp, 213 
"Setting the teeth on edge," 224 
Somaisthenic ideas, 225 
Spermatogams, 412 
"Spiny" cells of fibromata, 334 
Spirillaceo?, 414 
Spirillum sputugenum, 141, 452 
Spirochceta, 414 
Spirochceta denlium, 141 

Pallida, 20, 420 



Spirosoma, 414 

Stains on Nasmyth's membrane, 102 
Staphylococcus pyogenes albus, 139, 
140, 421 

Aureus, 421 

Citreus, 421 
Stomatitis, 348, 354 

Aphthous ("Thrush"), 354 

Catarrhal, 354 

Gangrenous, 354 

Herpetic, 354 

Mercurial, 354 

Syphilitic, 354 

Ulcerative, 354 
Streptococci, 425 

Streptococcus pyogenes, 139, 140, 413, 
420, 425, 427 

Virid'ans, 425 
Streptothrix actinomyces, 435 

Buccalis, 141 
Subcapsular odontocele, 400 
Synostosis (see Ankylosis). 
Syphilis of gum, 348 
Syphilitic dentine, 21 

Enamel, 19 

Stomatitis, 348, 354 
Systematic dental histories, 216 

Tanzer on blood pressure in pulp, 226, 

235 
Thallophyta, 413 
Thiobacteriacea, 415 
"Thrush," 354 

Tomes on calcification of pulp, 180 
On Fungoid excavation of teeth, 

34 
Tomes and Nowell on dental caries, 

106 
Torus palalinus, 330 
"Translucent zone" of caries, 116, 117, 

118, 119, 121, 142, 211 
Treponema, 414, 415, 438 
Trichomonas, 415, 421 
Truman on coagulants, 208 
Tuberculosis, 355 
Tumours, adenoma, 328, 343 
Carcinoma, 328, 343 
Connective tissue, 328 
Enchondroma, 328, 352 



INDEX 



477 



Tumours, endothelioma, 328 
Epithelial, 328 
Fibroma, 328, 330, 331 
Glandular, 328 
Hemangioma, 342 
Heterologous, 327 
Homologous, 327 
Innocent, 327 
Lipoma, 328 
Malignant, 327 
Of mandible, 330 
Of maxillae, 329 
Of palate, 330 
Osteoma, 330, 331, 343 
Papilloma, 330, 340 
Sarcoma, 328, 334, 337, 339, 352 
Teratoma, 328, 459 

Underwood on erosion, ^2 
Unna's cells, 326 

Vascular canals in dentine, 55 
Lesions of dental pulp, 232 
Vicentini on Lcptothrix racemosa, 451 

Walkhoff on atrophy of pulp, 195 
On affections of Nasmyth's mem- 
brane, 105 



Walkhoff on translucent zone of 

caries, 120 
Wedl on translucent zone of caries, 122 
Wellauer on translucent zone of caries, 

120 
Woods on absorption of enamel, 26 

Yeasts, 410, 412, 440, 441 

Znamensky on erosion of enamel, 31 
On "Pyorrhoea alveolaris," 272, 

303 
Zone of translucency, 116, 117 

Baume on, 120 

Bennett on, 118 

Black on, 118 

Complete decalcification, 114 

Leber and Rottenstein on, 1 1 8, 1 2 1 

Magitot on, 117 

Miller on, 117, 119 

Tomes on, 117 

Walkhoff on, 105, 120 

Wedl on, 118, 122 

Wellauer on, 120 
Zones in caries of enamel, 114 
Zsigmondy on hypoplasia of enamel 5 
Zygomycetes, 413, 421